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A366656
Number of divisors of 8^n+1.
9
2, 3, 4, 8, 4, 12, 16, 12, 8, 20, 48, 24, 16, 12, 64, 64, 8, 48, 64, 24, 16, 64, 64, 24, 32, 96, 768, 192, 32, 24, 1536, 24, 8, 256, 512, 1536, 64, 96, 256, 64, 64, 96, 1024, 48, 128, 1280, 256, 96, 128, 96, 8192, 1024, 32, 48, 1024, 2304, 256, 192, 256, 192
OFFSET
0,1
LINKS
FORMULA
a(n) = sigma0(8^n+1) = A000005(A062395(n)).
a(n) = A046798(3*n). - Max Alekseyev, Jan 09 2024
EXAMPLE
a(4)=4 because 8^4+1 has divisors {1, 17, 241, 4097}.
MAPLE
a:=n->numtheory[tau](8^n+1):
seq(a(n), n=0..100);
MATHEMATICA
DivisorSigma[0, 8^Range[0, 59] + 1] (* Paul F. Marrero Romero, Nov 12 2023 *)
PROG
(PARI) a(n) = numdiv(8^n+1);
KEYWORD
nonn
AUTHOR
Sean A. Irvine, Oct 15 2023
STATUS
approved