A208400 Smallest integer k such that k*n+1 is a prime dividing (n^n)^2 + 1.

8, 24, 16384, 8, 216, 1937780208, 24, 720, 167632, 22896, 8, 29256, 72, 2240, 3728099320468576, 8, 612214200, 64, 3800, 176, 40, 18624, 8, 160, 336, 19656, 280, 270006232334172274751152473116790619162839546306934626321438592627063115205009840, 8, 13392, 8568

Offset

2,1

Links

Table of n, a(n) for n=2..32.

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

Cf. A208399.

Sequence in context: A105063 A274303 A132586 * A103953 A076444 A023056

Adjacent sequences: A208397 A208398 A208399 * A208401 A208402 A208403

Keyword

nonn

Author

Michel Lagneau, Feb 27 2012

Status

approved