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 A017703 #17 Apr 02 2024 08:52:23
%S A017703 1,1048577,3486784402,1099512676353,95367431640626,1828080963947977,
%T A017703 79792266297612002,1152922604119523329,12157665462543713203,
%U A017703 50000047683716344601,672749994932560009202,638960608284819107651,19004963774880799438802,41834167608775550110577
%N A017703 Numerator of sum of -20th powers of divisors of n.
%C A017703 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 A017703 G. C. Greubel, <a href="/A017703/b017703.txt">Table of n, a(n) for n = 1..10000</a>
%F A017703 From _Amiram Eldar_, Apr 02 2024: (Start)
%F A017703 sup_{n>=1} a(n)/A017704(n) = zeta(20) (A013678).
%F A017703 Dirichlet g.f. of a(n)/A017704(n): zeta(s)*zeta(s+20).
%F A017703 Asymptotic mean: Limit_{m->oo} (1/m) * Sum_{k=1..m} a(k)/A017704(k) = zeta(21). (End)
%t A017703 Table[Numerator[DivisorSigma[20, n]/n^20], {n, 1, 20}] (* _G. C. Greubel_, Nov 05 2018 *)
%o A017703 (PARI) vector(20, n, numerator(sigma(n, 20)/n^20)) \\ _G. C. Greubel_, Nov 05 2018
%o A017703 (Magma) [Numerator(DivisorSigma(20,n)/n^20): n in [1..20]]; // _G. C. Greubel_, Nov 05 2018
%Y A017703 Cf. A017704 (denominator), A013678.
%K A017703 nonn,frac
%O A017703 1,2
%A A017703 _N. J. A. Sloane_