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A366638

Sum of the divisors of 7^n+1.

3, 15, 93, 660, 3606, 34560, 236964, 1559520, 9155916, 77423280, 530807472, 3868683120, 21224771760, 185094572580, 1261494915594, 9988783073280, 49990612274316, 436182213726030, 3279858902194056, 21372989348391720, 122709716651985624, 1082323574100172800

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OFFSET

0,1

LINKS

Max Alekseyev, Table of n, a(n) for n = 0..396

FORMULA

a(n) = sigma(7^n+1) = A000203(A034491(n)).

EXAMPLE

a(4)=3606 because 7^4+1 has divisors {1, 2, 1201, 2402}.

MAPLE

a:=n->numtheory[sigma](7^n+1):

seq(a(n), n=0..100);