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A366683
Number of divisors of 11^n-1.
14
4, 16, 16, 40, 12, 192, 16, 96, 32, 96, 16, 1920, 16, 128, 96, 448, 8, 1024, 8, 480, 768, 1024, 32, 18432, 128, 512, 64, 2560, 16, 9216, 32, 2048, 512, 256, 192, 20480, 64, 512, 4096, 4608, 512, 36864, 16, 10240, 384, 2048, 32, 1376256, 128, 4096, 512, 2560
OFFSET
1,1
LINKS
FORMULA
a(n) = sigma0(11^n-1) = A000005(A024127(n)).
EXAMPLE
a(3)=16 because 11^3-1 has divisors {1, 2, 5, 7, 10, 14, 19, 35, 38, 70, 95, 133, 190, 266, 665, 1330}.
MAPLE
a:=n->numtheory[tau](11^n-1):
seq(a(n), n=1..100);
MATHEMATICA
DivisorSigma[0, 11^Range[100]-1]
PROG
(PARI) a(n) = numdiv(11^n-1);
KEYWORD
nonn
AUTHOR
Sean A. Irvine, Oct 16 2023
STATUS
approved