cp's OEIS Frontend

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.

A015768 Numbers k such that phi(k) | sigma_10(k).

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%I A015768 #19 Sep 08 2022 08:44:40
%S A015768 1,2,3,6,22,33,66,166,250,375,498,750,1506,1826,5478,8250,10375,10873,
%T A015768 16566,17762,20750,21746,31125,32619,41666,53286,62250,62499,65238,
%U A015768 98250,110066,119603,124998,177153,195382,228250,239206
%N A015768 Numbers k such that phi(k) | sigma_10(k).
%C A015768 sigma_10(k) = A013958(k) is the sum of the 10th powers of the divisors of k.
%H A015768 Amiram Eldar, <a href="/A015768/b015768.txt">Table of n, a(n) for n = 1..623</a>
%t A015768 Select[Range[240000], Divisible[DivisorSigma[10, #], EulerPhi[#]] &] (* _Amiram Eldar_, Nov 06 2019 *)
%o A015768 (Magma)  [k:k in [1..240000]| IsIntegral(DivisorSigma(10,k)/EulerPhi(k))]; // _Marius A. Burtea_, Nov 06 2019
%Y A015768 Cf. A000010, A013958.
%Y A015768 Cf. A020492, A015759, A015761, A015762, A015763, A015764, A015765, A015766, A015767,  A015769, A015770, A015771, A015773, A015774, A094470.
%K A015768 nonn
%O A015768 1,2
%A A015768 _Robert G. Wilson v_