A175763 Least k such that k*n^n + 1 is prime.

1, 1, 4, 1, 12, 3, 4, 10, 10, 3, 86, 2, 40, 31, 28, 12, 8, 2, 34, 19, 28, 19, 116, 75, 4, 15, 110, 7, 8, 79, 42, 36, 14, 112, 80, 11, 30, 67, 78, 226, 170, 108, 96, 205, 272, 18, 54, 98, 42, 15, 78, 63, 362, 115, 292, 40, 170, 60, 350, 16, 366, 108, 234, 448, 128, 63, 42, 72

Offset: 1

Author

Charles R Greathouse IV, Aug 31 2010

Keywords

• nonn

Comments

By Linnik's theorem, a(n) = O(n^(L*n)) for some effectively computable L.

Links

• Charles R Greathouse IV, Table of n, a(n) for n = 1..1000

Crossrefs

Cf. A070855.

Programs

Mathematica

lk[n_]:=Module[{c=n^n,k=1},While[!PrimeQ[k*c+1],k++];k]; Array[lk,70] (* Harvey P. Dale, Apr 10 2019 *)

PARI

a(n)=my(N=n^n,k=1);while(!isprime(k*n^n+1),k++);k