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.

A067262 Numbers k such that sigma(k+1) = 4*phi(k).

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%I A067262 #13 Apr 24 2022 06:36:22
%S A067262 2,6,14,20,30,54,104,114,132,140,234,252,279,314,434,539,620,644,798,
%T A067262 860,1064,1080,1154,1287,1308,1500,1595,1715,1904,2232,2294,2375,2736,
%U A067262 2772,2925,3212,3219,3684,3834,4014,4070,4344,4464,4730,4959,5075,5159
%N A067262 Numbers k such that sigma(k+1) = 4*phi(k).
%H A067262 Amiram Eldar, <a href="/A067262/b067262.txt">Table of n, a(n) for n = 1..8225</a>
%t A067262 Select[Range[5000], DivisorSigma[1,#+1] == 4*EulerPhi[#] &] (* _Amiram Eldar_, Apr 24 2022 *)
%Y A067262 Cf. A000010, A000203, A067260, A067261, A067263.
%K A067262 nonn
%O A067262 1,1
%A A067262 _Benoit Cloitre_, Feb 21 2002