A085602 - OEIS

%I #19 Feb 27 2020 22:14:25

%S 2,28,3126,823544,387420490,285311670612,302875106592254,

%T 437893890380859376,827240261886336764178,1978419655660313589123980,

%U 5842587018385982521381124422,20880467999847912034355032910568,88817841970012523233890533447265626

%N Numbers of the form (2n+1)^(2n+1) + 1.

%C Also even Sierpinski numbers of the first kind.

%C No term is a square. Moreover, x^x + 1 != k^x, for if it were, we would have a counterexample to Fermat's Last Theorem.

%H Harvey P. Dale, <a href="/A085602/b085602.txt">Table of n, a(n) for n = 1..193</a>

%F a(n) = (2*n-1)^(2*n-1)+1. - _Alois P. Heinz_, Feb 27 2020

%t #^#+1&/@Range[1,21,2] (* _Harvey P. Dale_, Dec 08 2012 *)

%o (PARI) forstep(x=1,20,2,print1(x^x+1" "))

%Y Bisection of A014566 (odd part).

%K easy,nonn

%O 1,1

%A _Cino Hilliard_, Jul 07 2003