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 A049011 #22 Sep 05 2020 20:31:24
%S A049011 27,286,370,520,550,1332,13530,38220
%N A049011 Composite numbers k such that number of composite d with 3 < d < k, gcd(k, d) = 1, is pi(k).
%C A049011 Composite numbers k such that phi(k) + omega(k) = 2*pi(k) + 1. - _Jinyuan Wang_, Sep 05 2020
%e A049011 gcd(27,d)=1: d=4,8,10,14,16,20,22,25,26, pi(27)=9, so 27 is a term.
%o A049011 (PARI) isok(n) = {if (isprime(n) , return (0)); nb = 0; forcomposite (d=4, n-1, if (gcd(n, d) == 1, nb++);); return (nb == primepi(n));} \\ _Michel Marcus_, Jul 14 2013
%Y A049011 Cf. A036997.
%K A049011 nonn,fini,full
%O A049011 1,1
%A A049011 _Naohiro Nomoto_
%E A049011 a(6)-a(8) from _Michel Marcus_, Jul 14 2013