OFFSET
2,1
COMMENTS
a(73)>2475. - Ray Chandler, Jan 27 2005
EXAMPLE
2^2*(2^2-1)-1=11 prime so a(2)=2.
MATHEMATICA
f[n_] := Block[{k = 1, c}, While[c = n^k; ! PrimeQ[c*(c - 1) - 1], k++ ]; Return[k]; ]; Table[f[n], {n, 2, 72}] (* Ray Chandler, Jan 27 2005 *)
PROG
(PARI) a(n) = {my(k=1); while (!ispseudoprime(n^k*(n^k-1)-1), k++); k; } \\ Michel Marcus, Sep 16 2019
CROSSREFS
KEYWORD
nonn,more
AUTHOR
Pierre CAMI, Jan 24 2005
EXTENSIONS
a(55)-a(72) from Ray Chandler, Jan 27 2005
STATUS
approved