A086455 - OEIS

A086455

Sum of divisors of prime powers: sigma(p^e).

1, 3, 4, 7, 6, 8, 15, 13, 12, 14, 31, 18, 20, 24, 31, 40, 30, 32, 63, 38, 42, 44, 48, 57, 54, 60, 62, 127, 68, 72, 74, 80, 121, 84, 90, 98, 102, 104, 108, 110, 114, 133, 156, 128, 255, 132, 138, 140, 150, 152, 158, 164, 168, 183, 174, 180, 182, 192, 194, 198

(list; graph; refs; listen; history; text; internal format)

OFFSET

1,2

COMMENTS

a(n) = A000203(A000961(n)).

LINKS

R. J. Mathar, Table of n, a(n) for n = 1..10000

Eric Weisstein's World of Mathematics, Prime Power.

Eric Weisstein's World of Mathematics, Divisor Function

FORMULA

a(p^e) = (p^(e+1)-1)/(p-1): a(n)=(A025473(n)^(A025474(n)+1)-1)/(A025473(n)-1).

MAPLE