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 A351562 #6 Feb 23 2022 21:50:14 %S A351562 15,33,45,51,69,87,99,105,123,135,141,147,153,159,165,175,177,195,207, %T A351562 213,231,249,255,261,267,285,297,303,315,321,325,339,345,357,369,375, %U A351562 393,405,411,423,429,435,441,447,459,465,475,477,483,495,501,507,519,531,537,555,561,573,585,591,609,615,621,627,639 %N A351562 Odd composites k such that A342926(2*k) is a multiple of 3. %H A351562 <a href="/index/Si#SIGMAN">Index entries for sequences related to sigma(n)</a> %o A351562 (PARI) %o A351562 A003415(n) = if(n<=1, 0, my(f=factor(n)); n*sum(i=1, #f~, f[i, 2]/f[i, 1])); %o A351562 A342926(n) = (A003415(sigma(n))-n); %o A351562 isA351562(n) = ((n%2)&&!isprime(n)&&!(A342926(2*n)%3)); %Y A351562 Cf. A000203, A003415, A342925, A342926, A347880. %Y A351562 Cf. A347874 (the intersection of this sequence and A347872). %K A351562 nonn %O A351562 1,1 %A A351562 _Antti Karttunen_, Feb 23 2022