# Alternating Even-Odd Digit Palindromic Prime

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## Theorem

Let the notation $\left({abc}\right)_n$ be interpreted to mean $n$ consecutive repetitions of a string of digits $abc$ concatenated in the decimal representation of an integer.

The integer:

- $\left({10987654321234567890}\right)_{42} 1$

has the following properties:

- it is a palindromic prime with $841$ digits
- its digits are alternately odd and even.

## Proof

## Sources

- 1994: Harvey Dubner:
*Palindromic Primes with a Palindromic Prime Number of Digits*(*J. Recr. Math.***Vol. 26**,*no. 4*: 256)

- 1997: David Wells:
*Curious and Interesting Numbers*(2nd ed.) ... (previous) ... (next): $\left({10987654321234567890}\right)_{42} 1$