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 A073257 #17 Nov 21 2024 16:19:01
%S A073257 1,2,12,20,5,6,7,64,234,50,55,24,26,28,30,32,629,1008,209,220,231,
%T A073257 1012,506,168,425,182,189,2716,2204,1080,93,96,99,2176,105,4428,1369,
%U A073257 5586,1755,1800,6109,2478,2279,3916,5760,644,4606,1920,1960,10250,2040,2444
%N A073257 Smallest k such that gcd(c(k),k) = gcd(A002808(k),k) = A064814(k) = n.
%H A073257 Sean A. Irvine, <a href="/A073257/b073257.txt">Table of n, a(n) for n = 1..10000</a>
%F A073257 a(n) = min{x: gcd(c(x), x)=n}, where c(x) is the x-th composite number.
%e A073257 50th composite is 70, gcd(50,70)=10 appears first here, a(10)=50.
%t A073257 f[x_] := FixedPoint[x+PrimePi[ # ]+1&, x] t=Table[0, {100}]; Do[s=GCD[f[n], n]; If[s<101&&t[[s]]==0, t[[s]]=n], {n, 1, 100000}]; t
%Y A073257 Cf. A064814, A002808, A073258.
%K A073257 nonn
%O A073257 1,2
%A A073257 _Labos Elemer_, Jul 22 2002