A108829 Primes such that the outer 2 digits are n and n-1 and all inner digits are 1, where 0 < n < 9.

211, 2111, 8117, 41113, 411113, 8111111117, 2111111111111, 41111111111113, 811111111111111117, 2111111111111111111, 211111111111111111111111, 41111111111111111111111111111113, 41111111111111111111111111111111111111111111111111111113

Offset

1,1

Links

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

Mathematica

Sort[Select[Flatten[Table[FromDigits[Join[{n}, PadRight[{}, i, 1], {n-1}]], {n, 2, 8}, {i, 60}]], PrimeQ]] (* Harvey P. Dale, Mar 06 2014 *)

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: A303092 A361701 A086978 * A111480 A291075 A330426

Adjacent sequences: A108826 A108827 A108828 * A108830 A108831 A108832

Keyword

easy,nonn,base

Author

Cino Hilliard, Jul 11 2005

Extensions

More terms from Harvey P. Dale, Mar 06 2014

Status

approved