%I #6 Oct 24 2023 15:52:46

%S 3,3,6,56,258,6264,52136,1559520,17041416,706911048,10102223208,

%T 706019328000,9101898907920,519285252355776,11672709747324912,

%U 880565163670372352,18446811354131136516,1792353900753729655758,54357680125881245248800,4154723599066412190910560

%N a(n) is the sum of the divisors of n^n + 1.

%H Eric Weisstein's World of Mathematics, <a href="http://mathworld.wolfram.com/SierpinskiNumberoftheFirstKind.html">Sierpinski Number of the First Kind</a>

%F a(n) = A000203(A014566(n)).

%t {3}~Join~Array[DivisorSigma[1, #^# + 1] &, 19] (* _Michael De Vlieger_, Oct 24 2023 *)

%o (PARI) a(n) = sigma(n^n+1);

%Y Cf. A000203, A007571, A014566, A055385, A062727, A344859, A366819.

%K nonn

%O 0,1

%A _Sean A. Irvine_, Oct 24 2023