0,1

a(n) is never a perfect square because (2n)^(2n) is a positive square and the only squares that differ by 1 are 0 and 1. Sierpinski numbers are n^n+1. Hence this sequence is a subset of the Sierpinski numbers (A014566). - T. D. Noe, Mar 31 2006

Table of n, a(n) for n=0..10.

(PARI) forstep(x=0, 20, 2, print1(x^x+1" "))

Sequence in context: A137066 A175977 A121270 * A309675 A042341 A300900

Adjacent sequences: A085600 A085601 A085602 * A085604 A085605 A085606

easy,nonn

Cino Hilliard, Jul 07 2003

approved