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 A017693 #16 Apr 02 2024 08:50:02 %S A017693 1,32769,14348908,1073774593,30517578126,13061093507,4747561509944, %T A017693 35185445863425,205891146443557,500015258805447,4177248169415652, %U A017693 3851873211923611,51185893014090758,19446605389919367,48654880101420712,1152956690052710401,2862423051509815794 %N A017693 Numerator of sum of -15th powers of divisors of n. %C A017693 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 A017693 G. C. Greubel, <a href="/A017693/b017693.txt">Table of n, a(n) for n = 1..10000</a> %F A017693 From _Amiram Eldar_, Apr 02 2024: (Start) %F A017693 sup_{n>=1} a(n)/A017694(n) = zeta(15) (A013673). %F A017693 Dirichlet g.f. of a(n)/A017694(n): zeta(s)*zeta(s+15). %F A017693 Asymptotic mean: Limit_{m->oo} (1/m) * Sum_{k=1..m} a(k)/A017694(k) = zeta(16) (A013674). (End) %t A017693 Table[Numerator[DivisorSigma[15, n]/n^15], {n, 1, 20}] (* _G. C. Greubel_, Nov 06 2018 *) %o A017693 (PARI) vector(20, n, numerator(sigma(n, 15)/n^15)) \\ _G. C. Greubel_, Nov 06 2018 %o A017693 (Magma) [Numerator(DivisorSigma(15,n)/n^15): n in [1..20]]; // _G. C. Greubel_, Nov 06 2018 %Y A017693 Cf. A017694 (denominator), A013673, A013674. %K A017693 nonn,frac %O A017693 1,2 %A A017693 _N. J. A. Sloane_