OFFSET
0,1
LINKS
Eric Weisstein's World of Mathematics, Sierpinski Number of the First Kind
MATHEMATICA
{3}~Join~Array[DivisorSigma[1, #^# + 1] &, 19] (* Michael De Vlieger, Oct 24 2023 *)
PROG
(PARI) a(n) = sigma(n^n+1);
CROSSREFS
KEYWORD
nonn
AUTHOR
Sean A. Irvine, Oct 24 2023
STATUS
approved