Book:David Wells/Curious and Interesting Numbers

Contents

 * Introduction
 * A List of Mathematicians in Chronological Sequence
 * Glossary
 * Bibliography


 * The Dictionary


 * Tables
 * The First $100$ Triangular Numbers, Squares and Cubes
 * The First $20$ Pentagonal, Hexagonal, Heptagonal and Octagonal Numbers
 * The First $40$ Fibonacci Numbers
 * The Prime Numbers less than $1000$
 * The Factorials of the Numbers $1$ to $20$
 * The Decimal Reciprocals of the Primes from $7$ to $97$
 * The Factors of the Repunits from $11$ to $R_{40}$
 * The Factors, where Composite, and the Values of the Functions $\map \phi n$, $\map d n$ and $\map \sigma n$


 * Index



Positive Integer is Divisible by Sum of Consecutive Integers iff not Power of 2
$2$:

Decimal Expansion of $\pi$
$3 \cdotp 14159 \, 26535 \, 89793 \, 23846 \, 26433 \, 83279 \, 50288 \, 41972 \ldots$:

Leonhard Paul Euler
$3 \cdotp 14159 \, 26535 \, 89793 \, 23846 \, 26433 \, 83279 \, 50288 \, 41972 \ldots$: