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 A141230 #5 Dec 18 2018 11:11:26 %S A141230 15,33,39,49,55,57,81,87,95,111,113,143,159,177,183,201,209,249,281, %T A141230 289,295,303,319,321,335,353,393,407,415,417,447,489,519,529,535,537, %U A141230 543,551,577,583,591,593,617,625,633,649,655,681,695,737,767,807,815,879,895,913,951 %N A141230 Odd numbers n for which A006694((n-1)/2)=4. %C A141230 If p>3 is a prime then 3p is in this sequence if and only if p is in A001122. %o A141230 (PARI) a006694(n)=sumdiv(2*n+1, d, eulerphi(d)/znorder(Mod(2, d))) - 1; %o A141230 isok(n) = (n % 2) && (a006694((n-1)/2)== 4); \\ _Michel Marcus_, Dec 18 2018 %Y A141230 Cf. A006694, A001122, A001134. %K A141230 nonn %O A141230 1,1 %A A141230 _Vladimir Shevelev_, Jun 16 2008 %E A141230 More terms from _Michel Marcus_, Dec 18 2018