A087896 Least prime p such that n^p - (n-1)^p is composite.

11, 7, 5, 2, 3, 5, 2, 3, 5, 2, 5, 2, 2, 5, 3, 2, 2, 3, 2, 3, 3, 2, 5, 2, 2, 3, 2, 2, 3, 7, 2, 2, 3, 2, 3, 3, 2, 2, 3, 2, 7, 2, 2, 3, 2, 2, 2, 5, 2, 3, 3, 2, 3, 3, 2, 3, 2, 2, 2, 2, 2, 2, 5, 2, 3, 2, 2, 3, 3, 2, 2, 2, 2, 5, 3, 2, 2, 3, 2, 2, 5, 2, 3, 2, 2, 5, 2

Offset

2,1

Comments

The least n such that a(n) = p is found in A229073. - Eric M. Schmidt, Sep 12 2013

Links

Eric M. Schmidt, Table of n, a(n) for n = 2..10000

Mathematica

Table[p = 2; While[PrimeQ[n^p - (n - 1)^p], p = NextPrime[p]]; p, {n, 2, 88}] (* T. D. Noe, Sep 12 2013 *)

Prog

(PARI) a(n) = {forprime(p=2, default(primelimit), if(!isprime(n^p-(n-1)^p), return(p)))}

Crossrefs

Sequence in context: A305273 A236546 A155914 * A240598 A144262 A110093

Adjacent sequences: A087893 A087894 A087895 * A087897 A087898 A087899

Keyword

nonn

Author

Cino Hilliard, Oct 26 2003

Extensions

Edited by Charles R Greathouse IV, Nov 02 2009

Status

approved