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A108826 Primes such that the outer 2 digits are n and n+1 and all inner digits are 8, where 0 < n < 9. 0
283, 28888883, 88888888888889, 88888888888888889, 28888888888888888888888888883, 6888888888888888888888888888888887, 88888888888888888888888888888888889, 6888888888888888888888888888888888888888888888888888888888888888888888887, 28888888888888888888888888888888888888888888888888888888888888888888888883 (list; graph; refs; listen; history; text; internal format)
OFFSET

1,1

LINKS

Table of n, a(n) for n=1..9.

FORMULA

a(x) = 10^(x+1)*n+floor(10^x*8/9)*10+n+1. Output if a(x) is prime.

MATHEMATICA

Select[FromDigits/@Flatten[Table[Join[{n}, PadRight[{}, k, 8], {n+1}], {n, 8}, {k, 100}], 1], PrimeQ]//Sort (* Harvey P. Dale, Oct 09 2018 *)

PROG

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

CROSSREFS

Sequence in context: A142837 A064964 A263670 * A285890 A061310 A333930

Adjacent sequences:  A108823 A108824 A108825 * A108827 A108828 A108829

KEYWORD

easy,nonn,base

AUTHOR

Cino Hilliard, Jul 11 2005

EXTENSIONS

More terms from Harvey P. Dale, Oct 09 2018

STATUS

approved

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Last modified September 29 21:59 EDT 2020. Contains 337432 sequences. (Running on oeis4.)