OFFSET
1,5
COMMENTS
For n=64 (m=129), k > 2000 if k exists.
When k=1, the prime is of the form 4*n^2 + 4*n - 1 (or m^2 - 2).
MATHEMATICA
f[n_] := Block[{k = 1}, While[ !PrimeQ[((n + 1)^k)*(n^k - 1) - 1], k++ ]; k]; Table[ f[n], {n, 3, 128, 2}] (* Robert G. Wilson v, Aug 06 2005 *)
PROG
(PARI) a(n) = {my(k = 1); my(m = 2*n+1); while(! isprime((m+1)^k*(m^k-1) - 1), k++; ); k; } \\ Michel Marcus, Feb 06 2014
CROSSREFS
KEYWORD
more,nonn
AUTHOR
Pierre CAMI, Jan 29 2005
EXTENSIONS
Definition and comment edited by Michel Marcus, Feb 06 2014
a(27)=1 inserted by Michel Marcus, Feb 06 2014
STATUS
approved