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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
OFFSET
1,1
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: A064964 A372402 A263670 * A285890 A356219 A061310
KEYWORD
easy,nonn,base
AUTHOR
Cino Hilliard, Jul 11 2005
EXTENSIONS
More terms from Harvey P. Dale, Oct 09 2018
STATUS
approved