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A366616
Number of divisors of 5^n+1.
9
2, 4, 4, 12, 4, 8, 8, 16, 8, 32, 16, 32, 8, 16, 8, 96, 8, 16, 32, 32, 16, 576, 16, 16, 16, 32, 24, 320, 8, 16, 128, 32, 16, 384, 64, 128, 64, 32, 16, 192, 32, 64, 64, 64, 8, 512, 8, 32, 32, 128, 128, 768, 32, 32, 64, 128, 128, 384, 8, 64, 64, 64, 16, 24576, 16
OFFSET
0,1
LINKS
FORMULA
a(n) = sigma0(5^n+1) = A000005(A034474(n)).
EXAMPLE
a(3)=12 because 5^3+1 has divisors {1, 2, 3, 6, 7, 9, 14, 18, 21, 42, 63, 126}.
MAPLE
a:=n->numtheory[tau](5^n+1):
seq(a(n), n=0..100);
PROG
(PARI) a(n) = numdiv(5^n+1);
KEYWORD
nonn
AUTHOR
Sean A. Irvine, Oct 14 2023
STATUS
approved