This site is supported by donations to The OEIS Foundation.

 Please make a donation to keep the OEIS running. We are now in our 55th year. In the past year we added 12000 new sequences and reached 8000 citations (which often say "discovered thanks to the OEIS"). We need to raise money to hire someone to manage submissions, which would reduce the load on our editors and speed up editing. Other ways to donate

 Hints (Greetings from The On-Line Encyclopedia of Integer Sequences!)
 A076401 Sum of divisors of n-th perfect power. 2
 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 (list; graph; refs; listen; history; text; internal format)
 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

Lookup | Welcome | Wiki | Register | Music | Plot 2 | Demos | Index | Browse | More | WebCam
Contribute new seq. or comment | Format | Style Sheet | Transforms | Superseeker | Recent
The OEIS Community | Maintained by The OEIS Foundation Inc.

Last modified December 11 21:15 EST 2019. Contains 329937 sequences. (Running on oeis4.)