A108819 - OEIS

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A108819

Primes such that the outer 2 digits are n and n+1 and all inner digits are 2, where 0 < n < 9.

223, 829, 822229, 22222223, 822222229, 22222222223, 62222222222227, 822222222222229, 222222222222222222222222222222222223, 82222222222222222222222222222222222222222222222222222229

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OFFSET

1,1

LINKS

Table of n, a(n) for n=1..10.

FORMULA

a(x) = 10^(x+1)*n+floor(10^x*2/9)*10+n+1. Output if a(x) is prime.

PROG

(PARI) n10np1(n) = { local(x, y, k); for(x=1, n, for(k=1, 8, y=10^(x+1)*k+floor(10^x*2/9)*10+k+1; if(isprime(y), print1(y", ")) ) ) }

CROSSREFS

Sequence in context: A096660 A345198 A094459 * A158226 A253953 A205273

Adjacent sequences: A108816 A108817 A108818 * A108820 A108821 A108822

KEYWORD

easy,nonn,base

AUTHOR

Cino Hilliard, Jul 11 2005

STATUS

approved