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A344859
a(n) is the number of divisors of n^n + 1.
5
2, 2, 2, 6, 2, 8, 8, 16, 8, 16, 8, 96, 16, 32, 48, 160, 4, 12, 288, 48, 8, 64, 16, 512, 64, 128, 32, 3072, 64, 128, 1024, 384, 16, 2048, 64, 18432, 32, 128, 192, 512, 768, 64, 1024, 384, 256, 16384, 256, 2560, 64, 192, 1024, 3072, 32, 512, 16384, 4096, 128, 8192, 8192, 768, 4096, 256, 128, 1376256, 16
OFFSET
0,1
LINKS
Tyler Busby, Table of n, a(n) for n = 0..148 (terms 0..123 from Max Alekseyev)
Eric Weisstein's World of Mathematics, Sierpinski Number of the First Kind
FORMULA
a(n) = A000005(A014566(n)).
MATHEMATICA
a[0] = 2; a[n_] := DivisorSigma[0, n^n + 1]; Array[a, 45, 0] (* Amiram Eldar, May 31 2021 *)
PROG
(PARI) a(n) = numdiv(n^n+1);
CROSSREFS
Cf. A007571 (Lpf), A055385 (lpf).
Sequence in context: A074928 A285713 A278230 * A230940 A110512 A078020
KEYWORD
nonn
AUTHOR
Seiichi Manyama, May 31 2021
STATUS
approved