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 A015767 #11 Feb 18 2021 11:06:04 %S A015767 1,2,3,6,12,14,15,30,35,38,42,54,56,70,78,87,95,105,114,126,135,140, %T A015767 147,168,174,182,190,209,210,215,216,222,248,258,264,266,270,285,294, %U A015767 297,315,342,357,378,418,420,430,447,455,456,494,518,540,546 %N A015767 Numbers k such that phi(k) | sigma_9(k). %C A015767 sigma_9(n) = A013957(n) is the sum of the 9th powers of the divisors of n. %H A015767 Amiram Eldar, <a href="/A015767/b015767.txt">Table of n, a(n) for n = 1..10000</a> %t A015767 Select[Range[500], Divisible[DivisorSigma[9, #], EulerPhi[#]] &] (* _Amiram Eldar_, Nov 02 2019 *) %Y A015767 Cf. A000010, A013957. %Y A015767 Cf. A020492, A015759, A015761, A015762, A015763, A015764, A015765, A015766, A015768, A015769, A015770, A015771, A015773, A015774, A094470. %K A015767 nonn %O A015767 1,2 %A A015767 _Robert G. Wilson v_ %E A015767 Offset corrected by _Amiram Eldar_, Nov 02 2019