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 A333847 #11 Jul 19 2021 01:22:05
%S A333847 0,0,1,3,1,7,3,11,15,7,15,13,31,3,13,3,17,23,63,19,39,27,63,65,43,69,
%T A333847 127,51,35,91,81,39,15,1,237,9,51,255,47,115,105,281,87,33,117,121,87,
%U A333847 33,59,207,181,63,235,511,141,409,243,517,87,343,295,249,75,615,363
%N A333847 a(n) = A063514(A028982(n)).
%C A333847 Except for the first 2 terms, all terms are odd.
%H A333847 Michel Marcus, <a href="/A333847/b333847.txt">Table of n, a(n) for n = 1..5000</a>
%o A333847 (PARI) lista(nn) = {for (n=1, nn, if (issquare(n) || (!(n%2) && issquare(n/2)), print1(sigma(n) % eulerphi(n), ", ");););}
%Y A333847 Cf. A028982 (squares and twice squares), A063514 (sigma(n) mod phi(n)), A072808.
%K A333847 nonn
%O A333847 1,4
%A A333847 _Michel Marcus_, Apr 08 2020