A108836 Primes such that the outer 2 digits are n and n-1 and all inner digits are 8, where 0 < n < 9.

281, 887, 8887, 48883, 888887, 888888887, 48888888883, 888888888887, 2888888888881, 4888888888883, 48888888888883, 2888888888888888888888888881, 48888888888888888888888888888888888888883

Offset

1,1

Links

Table of n, a(n) for n=1..13.

Mathematica

Sort[Select[Flatten[Table[FromDigits[Join[{n}, PadRight[{}, k, 8], {n-1}]], {n, 2, 8, 2}, {k, 50}]], PrimeQ]] (* Harvey P. Dale, Mar 08 2023 *)

Prog

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

Crossrefs

Sequence in context: A163184 A122710 A161191 * A295983 A264150 A289543

Adjacent sequences: A108833 A108834 A108835 * A108837 A108838 A108839

Keyword

easy,nonn,base

Author

Cino Hilliard, Jul 11 2005

Status

approved