OFFSET
2,1
EXAMPLE
a(3) = 24 because (3^3)^2 + 1 =2*5*73 and the smallest prime divisor of the form k*n+1 is 73 = 24*3+1 => k = 24.
MATHEMATICA
Table[p=First/@FactorInteger[(n^n)^2+1]; (Select[p, Mod[#1, n] == 1 &, 1][[1]]
- 1)/n, {n, 2, 20}]
CROSSREFS
KEYWORD
nonn
AUTHOR
Michel Lagneau, Feb 27 2012
STATUS
approved