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 A049012 #18 Oct 29 2019 13:50:10
%S A049012 33,75,94,106,118,1540,2442,5340
%N A049012 Composite numbers n such that number of nonprime d with 0 < d < n, gcd(n,d)=1, is pi(n).
%C A049012 Numbers n such that 2*A000720(n) = A000010(n) + A001221(n). - _Max Alekseyev_, Aug 22 2013
%C A049012 The sequence is finite since the l.h.s. grows as 2n/log(n), while the r.h.s. is asymptotically at least A080130*n/log(log(n)). In fact, known bounds for A000720 and A000010 imply that there are no terms above 10^7, and thus the sequence is full. - _Max Alekseyev_, Oct 29 2019
%e A049012 gcd(33,d)=1: d=1,4,8,10,14,16,20,25,26,28,32, pi(33)=11, so 33 is a term.
%o A049012 (PARI) isok(n) = {if (isprime(n) , return (0)); nb = 0; for (d=1, n-1, if (! isprime(d) && gcd(n, d) == 1, nb++);); return (nb == primepi(n));} \\ _Michel Marcus_, Jul 14 2013
%K A049012 nonn,fini,full
%O A049012 1,1
%A A049012 _Naohiro Nomoto_
%E A049012 More terms from _Michel Marcus_, Jul 14 2013
%E A049012 Keywords fini, full added by _Max Alekseyev_, Oct 29 2019