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 A058012 #8 Jul 17 2022 23:30:36
%S A058012 4,6,10,12,14,36,39,42,45,48,124,128,132,140,345,365,370,375,380,385,
%T A058012 390,1086,1140,3101,3122,8416,8480,24309,24318,64550,64560,64570,
%U A058012 64590,64600,64660,64730,175208,175219,175230,176616,480876,480888,480948
%N A058012 Consider the sequence {b(m)} of composite numbers (excluding 1); sequence gives values of b(m) where gcd(m, b(m)) increases.
%e A058012 a(4) = 12 because twelve is the sixth composite number and gcd(6,12) > gcd(5,10).
%t A058012 r=0; Do[a = GCD[n, n - PrimePi[n] -1]; If[a > r, r = a; Print[n]], {n, 1, 10^6} ]
%Y A058012 Cf. A058011.
%K A058012 nonn
%O A058012 1,1
%A A058012 _Robert G. Wilson v_, Nov 13 2000
%E A058012 Title corrected by _Sean A. Irvine_, Jul 17 2022