# Category:Mistakes/Curious and Interesting Numbers

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This category reports on mistakes in *Curious and Interesting Numbers* by David Wells.

## Pages in category "Mistakes/Curious and Interesting Numbers"

The following 200 pages are in this category, out of 222 total.

(previous page) (next page)### 1

### 2

### 3

### 4

### 9

### A

- Definition:Ackermann Function/Mistake 1
- Definition:Ackermann Function/Mistake 2
- Amicable Pair with Smallest Common Prime Factor 5/Mistake
- Amicable Pair/Examples/59,554, 936,495, 441,481, 044,788, 091,271, 148,664, 944,796, 300,859, 243,635, 311,219, 048,448 - 59,554, 936,495, 441,891, 385,123, 332,422, 108,719, 776,971, 992,921, 810,832, 072,976, 105,472/Mistake
- Amicable Pairs with Common Factor 3/Mistake
- Definition:Apothecaries' Ounce/Mistake
- Definition:Arabic Numerals/Historical Note/Mistake
- Archimedes' Cattle Problem/Mistake

### C

- Carmichael Number with 4 Prime Factors/Mistake
- Carmichael's Theorem/Mistake
- Consecutive Integers whose Product is Primorial/Mistake
- Consecutive Integers whose Product is Primorial/Mistake/First Edition
- Consecutive Integers whose Product is Primorial/Mistake/Second Edition
- Consecutive Powerful Numbers/Mistake
- Construction of Smith Number from Prime Repunit/Mistake
- Continued Square Root of 1, 2, 3, 4, .../Mistake

### D

- Book:David Wells/Curious and Interesting Numbers/Errata
- Book:David Wells/Curious and Interesting Numbers/Second Edition/Errata
- Definition:Deltahedron/Mistake
- Difference between Two Squares equal to Repunit/Mistake
- Divisibility of Elements of Pythagorean Triple by 7/Mistake
- Divisor Count of 108/Mistake
- Doubling the Cube/Historical Note/Mistake

### E

- Element of Pascal's Triangle is Sum of Diagonal or Column starting above it going Upwards/Mistake
- Euler Lucky Number/Examples/41/Mistake
- Euler-Binet Formula/Corollary 1/Mistake
- Even Integer with Abundancy Index greater than 9/Mistake
- Existence of Number to Power of Prime Minus 1 less 1 divisible by Prime Squared/Mistake

### F

- Factorial as Product of Consecutive Factorials/Mistake
- Feit-Thompson Conjecture/Stronger/Mistake
- Feit-Thompson Conjecture/Stronger/Mistake/First Edition
- Feit-Thompson Conjecture/Stronger/Mistake/Second Edition
- Definition:Fermat Pseudoprime/Base 4/Mistake
- Fibonacci Number as Sum of Binomial Coefficients/Mistake
- Fibonacci Number as Sum of Binomial Coefficients/Mistake/First Edition
- Fibonacci Number as Sum of Binomial Coefficients/Mistake/Second Edition
- Definition:Fischer-Griess Monster/Historical Note/Mistake
- Fourth Powers which are Sum of 4 Fourth Powers/Mistake

### G

### H

### I

- Integer as Sum of 5 Non-Zero Squares/Mistake
- Integer both Square and Triangular/Mistake
- Integer which is Multiplied by 9 when moving Last Digit to First/Mistake
- Integer whose Digits when Grouped in 3s add to Multiple of 999 is Divisible by 999/Mistake
- Integers such that Difference with Power of 2 is always Prime/Mistake
- Integers whose Divisor Sum equals Half Phi times Divisor Count/Mistake
- Integers whose Divisor Sum is Cube/Mistake
- Integers with Prime Values of Divisor Sum/Mistake

### K

### L

### M

- Definition:Magic Hexagon/Mistake
- Mersenne Number whose Index is Mersenne Prime/Mistake
- Definition:Mersenne Number/Mistake
- Multiple of 999 can be Split into Groups of 3 Digits which Add to 999/Mistake
- Multiplicative Magic Square/Examples/Order 3/Smallest/Historical Note/Mistake
- Multiply Perfect Number of Order 8/Mistake

### N

- No 4 Fibonacci Numbers can be in Arithmetic Sequence/Mistake
- Non-Palindromes in Base 2 by Reverse-and-Add Process/Mistake
- Number of Different Ways to play First n Moves in Chess/Mistake
- Number of Fibonacci Numbers with Same Number of Decimal Digits/Mistake
- Number of Primes up to n Approximates to Eulerian Logarithmic Integral/Mistake
- Number times Recurring Part of Reciprocal gives 9-Repdigit/Mistake
- Number times Recurring Part of Reciprocal gives 9-Repdigit/Mistake/First Edition
- Number times Recurring Part of Reciprocal gives 9-Repdigit/Mistake/Second Edition
- Numbers equal to Sum of Primes not Greater than its Prime Counting Function Value/Mistake
- Numbers Not Expressible as Sum of no more than 5 Squares of Composite Numbers/Mistake
- Numbers such that Divisor Count divides Phi divides Divisor Sum/Mistake
- Numbers whose Cube equals Sum of Sequence of that many Squares/Mistake
- Numbers whose Difference equals Difference between Cube and Seventh Power/Mistake
- Numbers with Square-Free Binomial Coefficients/Mistake

### O

### P

- Palindromic Smith Number/Examples/123,455,554,321/Mistake
- Palindromic Triangular Numbers/Mistake 1
- Palindromic Triangular Numbers/Mistake 2
- Pandigital Integers remaining Pandigital on Multiplication/Mistake
- Pascal's Rule/Mistake
- Pentagonal and Hexagonal Numbers/Mistake
- Perfect Digit-to-Digit Invariant/Examples/3435/Mistake
- Perfect Number is Sum of Successive Odd Cubes except 6/Mistake
- Definition:Perfect Number/Historical Note/Mistake 1
- Definition:Perfect Number/Historical Note/Mistake 2
- Period of Reciprocal of 729 is 81/Mistake
- Definition:Pi/Decimal Expansion/Mistake
- Definition:Pi/Historical Note/Modern Developments/Mistake
- Definition:Pi/Historical Note/Notation/Mistake
- Definition:Plato's Geometrical Number/Mistake
- Polydivisible Number/Examples/381,654,729/Mistake
- Positive Integer is Sum of Consecutive Positive Integers iff not Power of 2/Mistake/First Edition
- Positive Integer is Sum of Consecutive Positive Integers iff not Power of 2/Mistake/Second Edition
- Prime between n and 9 n divided by 8/Mistake
- Prime Decomposition of 5th Fermat Number/Mistake
- Prime Decomposition of 7th Fermat Number/Mistake
- Prime Factors of 35, 36, 4734 and 4735/Mistake
- Prime Magic Square/Examples/Order 12/Smallest with Consecutive Primes from 3/Mistake
- Prime Numbers which Divide Sum of All Lesser Primes/Mistake/First Edition
- Prime Numbers which Divide Sum of All Lesser Primes/Mistake/Second Edition
- Prime to Own Power minus 1 over Prime minus 1 being Prime/Mistake/Wells
- Primes not Sum of or Difference between Powers of 2 and 3/Mistake
- Probability of All Players receiving Complete Suit at Bridge/Mistake
- Product of Sequence of Fermat Numbers plus 2/Mistake
- Product of Two Triangular Numbers to make Square/Mistake
- Product with Repdigit can be Split into Parts which Add to Repdigit/Mistake
- Products of 2-Digit Pairs which Reversed reveal Same Product/Mistake
- Properties of Family of 333,667 and Related Numbers/Mistake
- Pythagorean Triangle with Sides in Arithmetic Sequence/Mistake
- Pépin's Test/Mistake

### R

### S

- Sam Loyd's Missing Square/Mistake
- Schatunowsky's Theorem/Mistake
- Definition:Semiperfect Number/Mistake
- Sequence of 9 Consecutive Integers each with 48 Divisors/Mistake
- Sequence of Fibonacci Numbers ending in Index/Mistake
- Sequence of Integers whose Factorial plus 1 is Prime/Mistake
- Sequence of Prime Primorial minus 1/Mistake
- Sequence of Square Centered Hexagonal Numbers/Mistake
- Sequence of Triplets of Primitive Pythagorean Triangles with Same Area/Mistake
- Set of 3 Integers each Divisor of Sum of Other Two/Mistake
- Sets of 4 Prime Quadruples/Mistake
- Smallest Fermat Pseudoprime to Bases 2, 3, 5 and 7/Mistake
- Smallest Fourth Power as Sum of 5 Distinct Fourth Powers/Mistake
- Smallest Integer not Sum of Two Ulam Numbers/Mistake
- Smallest Integer which is Product of 4 Triples all with Same Sum/Mistake
- Smallest Number which is Multiplied by 99 by Appending 1 to Each End/Mistake
- Smallest Number which is Sum of 4 Triples with Equal Products/Mistake
- Smallest Odd Number not of form 2 a squared plus p/Mistake
- Smallest Penholodigital Square/Mistake
- Smallest Positive Integer not of form +-4 mod 9 not representable as Sum of Three Cubes/Mistake
- Smallest Set of Weights for Two-Pan Balance/Mistake
- Sociable Chain/Examples/12,496/Mistake
- Solution of Ljunggren Equation/Mistake
- Solutions of Diophantine Equation x^4 + y^4 = z^2 + 1 for x = 239/Mistake
- Solutions of Ramanujan-Nagell Equation/Mistake
- Solutions to Approximate Fermat Equation x^3 = y^3 + z^3 Plus or Minus 1/Mistake
- Solutions to p^2 Divides 10^p - 10/Mistake
- Solutions to x^3 + y^3 + z^3 = 6xyz/Mistake
- Definition:Speed of Light/Mistake
- Spherical Law of Sines/Historical Note/Mistake
- Square Numbers which are Divisor Sum values/Mistake
- Square Numbers which are Sum of Consecutive Powers/Mistake
- Square Numbers which are Sum of Sequence of Odd Cubes/Mistake
- Square of Hypotenuse of Pythagorean Triangle is Difference of two Cubes/Mistake
- Square of Small Repunit is Palindromic/Mistake
- Square of Small Repunit is Palindromic/Mistake/First Edition
- Square of Small Repunit is Palindromic/Mistake/Second Edition
- Squares Ending in 5 Occurrences of 2-Digit Pattern/Mistake
- Squares whose Digits can be Separated into 2 other Squares/Mistake