A076401 Sum of divisors of n-th perfect power.

1, 7, 15, 13, 31, 31, 40, 63, 91, 57, 127, 121, 217, 133, 156, 255, 403, 183, 399, 600, 403, 364, 511, 307, 847, 400, 381, 961, 741, 931, 1023, 553, 1651, 781, 1281, 1093, 1767, 871, 2821, 993, 2340, 2047, 1729, 2149, 1767, 3751, 1464, 1407, 2667, 2379

Offset

1,2

Links

Amiram Eldar, Table of n, a(n) for n = 1..10000

Eric Weisstein's World of Mathematics, Perfect Powers.

Eric Weisstein's World of Mathematics, Divisor Function.

Formula

a(n) = A000203(A001597(n)).

Maple

N:= 10^4: # to use all perfect powers <= N
L:= sort(convert({seq(seq(i^k, i=1..floor(N^(1/k))), k=2..ilog2(N))}, list)):
map(numtheory:-sigma, L); # Robert Israel, Oct 02 2014

Prog

(PARI) lista(nn) = {for (n=1, nn, if ((n==1) || ispower(n), print1(sigma(n), ", ")); ); } \\ Michel Marcus, Oct 02 2014

Crossrefs

Cf. A000203, A001597, A076400.

Sequence in context: A290621 A290629 A234861 * A180114 A204740 A244536

Adjacent sequences: A076398 A076399 A076400 * A076402 A076403 A076404

Keyword

nonn

Author

Reinhard Zumkeller, Oct 09 2002

Status

approved