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A366653
Sum of the divisors of 8^n-1.
12
8, 104, 592, 8736, 38912, 473600, 2466048, 38054016, 155493536, 2015330304, 10359014400, 166290432000, 636328345600, 7645340651520, 42424026529792, 648494317126656, 2599936977797120, 32817383473149440, 164708609085669376, 3010983668199456768
OFFSET
1,1
LINKS
FORMULA
a(n) = sigma(8^n-1) = A000203(A024088(n)).
a(n) = A075708(3*n). - Max Alekseyev, Jan 09 2024
EXAMPLE
a(5)=38912 because 8^5-1 has divisors {1, 7, 31, 151, 217, 1057, 4681, 32767}.
MAPLE
a:=n->numtheory[sigma](8^n-1):
seq(a(n), n=1..100);
MATHEMATICA
DivisorSigma[1, 8^Range[30]-1]
KEYWORD
nonn
AUTHOR
Sean A. Irvine, Oct 15 2023
STATUS
approved