OFFSET
2,1
COMMENTS
The values of k are in A187024.
LINKS
Amiram Eldar, Table of n, a(n) for n = 2..148 (terms 2..100 from Vincenzo Librandi)
EXAMPLE
12^12+1 = 89*193*233*2227777; the smallest prime divisor of the form k*n+1 is 193 = 16*12+1, hence a(12) = 193.
MATHEMATICA
Table[p=First/@FactorInteger[n^n+1]; Select[p, Mod[#1, n] == 1 &, 1][[1]], {n, 2, 40}]
PROG
(Magma) A187022:=function(n); for d in PrimeDivisors(n^n+1) do if d mod n eq 1 then return d; end if; end for; return 0; end function; [ A187022(n): n in [2..40] ]; // Klaus Brockhaus, Mar 02 2011
CROSSREFS
KEYWORD
nonn
AUTHOR
Michel Lagneau, Mar 02 2011
STATUS
approved