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A108820 Primes such that the outer 2 digits are n and n+1 and all inner digits are 3, where 0 < n < 9. 0
233, 839, 2333, 6337, 23333, 63337, 83339, 633337, 6333337, 8333333339, 23333333333, 63333333337, 83333333339, 63333333333337, 8333333333333339, 23333333333333333, 23333333333333333333333 (list; graph; refs; listen; history; text; internal format)
OFFSET

1,1

LINKS

Table of n, a(n) for n=1..17.

FORMULA

a(x) = 10^(x+1)*n+floor(10^x*3/9)*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*3/9)*10+k+1; if(isprime(y), print1(y", ")) ) ) }

CROSSREFS

Sequence in context: A142783 A142848 A023338 * A230392 A003537 A037033

Adjacent sequences:  A108817 A108818 A108819 * A108821 A108822 A108823

KEYWORD

easy,nonn,base

AUTHOR

Cino Hilliard, Jul 11 2005

EXTENSIONS

Corrected by T. D. Noe, Nov 15 2006

STATUS

approved

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Last modified April 18 12:34 EDT 2019. Contains 322209 sequences. (Running on oeis4.)