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 A073258 #15 Jul 19 2020 08:16:55
%S A073258 1,3,4,8,9,11,13,17,19,23,25,27,29,31,33,35,37,38,39,40,41,43,44,45,
%T A073258 46,47,49,53,57,58,59,61,66,67,68,69,71,73,79,83,84,85,86,87,88,89,90,
%U A073258 91,92,94,95,97,100,101,103,106,107,108,109,111,113,115,116,117,118,119
%N A073258 Numbers n such that gcd(c(n),n) = gcd(A002808(n),n) = A064814(n)=1 where c(n) is the n-th composite number.
%e A073258 n=256: composite(256) = 323 = 17*19, gcd(323,256)=1, so 256 is a term.
%t A073258 c[x_] := FixedPoint[x+PrimePi[ # ]+1&, x]; t=Table[0, {256}]; s=0; k=0; Do[s=GCD[c[n], n]; If[Equal[s, 1], k=k+1; t[[k]]=n; Print[{k, n}]], {n, 1, 256}] t
%o A073258 (PARI) lista(nn) = {my(n=0, list=List()); forcomposite (c=1, nn, n++; if (gcd(n, c) == 1, listput(list, c))); Vec(list); } \\ _Michel Marcus_, Jul 19 2020
%Y A073258 Cf. A064814, A002808, A073257.
%K A073258 nonn
%O A073258 1,2
%A A073258 _Labos Elemer_, Jul 22 2002