This is a front-end for the Online Encyclopedia of Integer Sequences, made by Christian Perfect. The idea is to provide OEIS entries in non-ancient HTML, and then to think about how they're presented visually. The source code is on GitHub.
%I A017691 #16 Apr 02 2024 04:09:48 %S A017691 1,16385,4782970,268451841,6103515626,39184481725,678223072850, %T A017691 4398314962945,22876797237931,10000610353201,379749833583242, %U A017691 213999516991295,3937376385699290,5556342524323625,5838586426737844,72061992352890881,168377826559400930,374836322743499435 %N A017691 Numerator of sum of -14th powers of divisors of n. %C A017691 Sum_{d|n} 1/d^k is equal to sigma_k(n)/n^k. So sequences A017665-A017712 also give the numerators and denominators of sigma_k(n)/n^k for k = 1..24. The power sums sigma_k(n) are in sequences A000203 (k=1), A001157-A001160 (k=2,3,4,5), A013954-A013972 for k = 6,7,...,24. - Ahmed Fares (ahmedfares(AT)my-deja.com), Apr 05 2001 %H A017691 G. C. Greubel, <a href="/A017691/b017691.txt">Table of n, a(n) for n = 1..10000</a> %F A017691 From _Amiram Eldar_, Apr 02 2024: (Start) %F A017691 sup_{n>=1} a(n)/A017692(n) = zeta(14) (A013672). %F A017691 Dirichlet g.f. of a(n)/A017692(n): zeta(s)*zeta(s+14). %F A017691 Asymptotic mean: Limit_{m->oo} (1/m) * Sum_{k=1..m} a(k)/A017692(k) = zeta(15) (A013673). (End) %t A017691 Table[Numerator[DivisorSigma[14, n]/n^14], {n, 1, 20}] (* _G. C. Greubel_, Nov 06 2018 *) %o A017691 (PARI) vector(20, n, numerator(sigma(n, 14)/n^14)) \\ _G. C. Greubel_, Nov 06 2018 %o A017691 (Magma) [Numerator(DivisorSigma(14,n)/n^14): n in [1..20]]; // _G. C. Greubel_, Nov 06 2018 %Y A017691 Cf. A017692 (denominator), A013672, A013673. %K A017691 nonn,frac %O A017691 1,2 %A A017691 _N. J. A. Sloane_