login
The OEIS Foundation is supported by donations from users of the OEIS and by a grant from the Simons Foundation.

 

Logo


Hints
(Greetings from The On-Line Encyclopedia of Integer Sequences!)
A087896 Least prime p such that n^p - (n-1)^p is composite. 2
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 (list; graph; refs; listen; history; text; internal format)
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

Lookup | Welcome | Wiki | Register | Music | Plot 2 | Demos | Index | Browse | More | WebCam
Contribute new seq. or comment | Format | Style Sheet | Transforms | Superseeker | Recent
The OEIS Community | Maintained by The OEIS Foundation Inc.

License Agreements, Terms of Use, Privacy Policy. .

Last modified January 29 08:12 EST 2020. Contains 331337 sequences. (Running on oeis4.)