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 A015763 #20 Sep 08 2022 08:44:40 %S A015763 1,2,3,6,12,14,15,30,35,42,46,56,70,78,105,134,138,140,161,168,184, %T A015763 190,210,230,248,264,270,299,322,357,402,414,418,420,483,552,570,594, %U A015763 598,616,623,630,644,670,690,714,744,805,812,840,874,897,910 %N A015763 Numbers k such that phi(k) divides sigma_5(k). %C A015763 sigma_5(n) is the sum of the 5th powers of the divisors of n. %H A015763 David A. Corneth, <a href="/A015763/b015763.txt">Table of n, a(n) for n = 1..10000</a> %e A015763 sigma_5(12) = 1^5 + 2^5 + 3^5 + 4^5 + 6^5 + 12^5 = 257908. phi(12) = 4. sigma_5(12) = 257908 is divisible by phi(12) = 4 so 12 is in the sequence. - _David A. Corneth_, Aug 24 2019 %t A015763 Select[Range[910], Divisible[DivisorSigma[5, #], EulerPhi[#]] &] (* _Jon Maiga_, Aug 24 2019 *) %o A015763 (PARI) isok(n) = !(sigma(n, 5) % eulerphi(n)); \\ _Michel Marcus_, Aug 24 2019 %o A015763 (Magma) [k:k in [1..1000]| DivisorSigma(5,k) mod EulerPhi(k) eq 0]; // _Marius A. Burtea_, Aug 24 2019 %Y A015763 Cf. A000010, A001160. %K A015763 nonn,easy %O A015763 1,2 %A A015763 _Robert G. Wilson v_