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 A177204 #19 Mar 27 2023 03:38:49
%S A177204 15,33,35,39,51,55,65,69,77,85,87,111,115,119,123,141,143,153,155,159,
%T A177204 161,175,177,183,187,201,205,209,213,219,221,235,245,247,249,253,255,
%U A177204 265,267,287,291,295,299,303,305,309,319,321,323,325,327,329,339,341,363,371,377,391,393,403,407,411,413,415
%N A177204 Pseudoperfect totient numbers (A288452) which are not powers of primes (A000961).
%C A177204 A proper subset of A288452. All odd primes and all powers of 3 are pseudoperfect totient numbers. First term which has k factors counting multiplicity >1: 15, 153, 875, 4375, 62451, etc. First term which has k distinct factors >1: 15, 255, 21505, etc.
%H A177204 Amiram Eldar, <a href="/A177204/b177204.txt">Table of n, a(n) for n = 1..10000</a>
%t A177204 fQ[n_] := Module[{tots = Rest@ NestWhileList[ EulerPhi, n, # > 1 &]}, MemberQ[Total /@ Subsets[tots, Length[ tots]], n]]; Select[ Range[ 3, 440, 2], fQ@# && !PrimePowerQ@# &]
%Y A177204 Cf. A288452, A000961.
%K A177204 nonn,easy
%O A177204 1,1
%A A177204 _Amiram Eldar_ and _Robert G. Wilson v_, Jul 02 2017