A191715 Nonprime numbers of the form n*(n-1)^n - (n-1)*n^(n-1) + 1.

1, 133, 54871, 1253659, 31438345, 863585785, 25867844011, 840625753991, 29488048443085, 1111334648458165, 44804977347486175, 1924820469011714611, 87800711122303545361, 4238935318038328143857, 11582179256389013503203871, 652184749150919163867112021

Offset: 1

Author

Juri-Stepan Gerasimov, Jun 12 2011

Keywords

• nonn

Comments

If n=3, then 3*2^3-2*3^2+1=7 is prime, so 7 is not in this sequence. If n=5, then 5*4^5-4*5^4+1=2621 is prime.

Links

• Charles R Greathouse IV, Table of n, a(n) for n = 1..377

Crossrefs

Cf. A191409, A191699.

Programs

Magma

[ a: n in [2..40] | not IsPrime(a) where a is n*(n-1)^n-(n-1)*n^(n-1)+1 ]; // Vincenzo Librandi, Jun 13 2011

Mathematica

Union[Select[Table[n(n-1)^n-(n-1)n^(n-1)+1,{n,30}],!PrimeQ[#]&]] (* Harvey P. Dale, Jun 19 2011 *)

PARI

for(n=1,1e3,if(!ispseudoprime(k=n*(n-1)^n-(n-1)*n^(n-1)+1),print1(k", ")))