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 A094521 #14 Oct 18 2019 23:05:39
%S A094521 1,1,2,1,2,1,4,3,2,1,4,1,2,5,8,1,6,1,4,3,2,1,8,5,2,9,4,1,10,1,16,11,2,
%T A094521 5,12,1,2,3,8,1,6,1,4,15,2,1,16,7,10,3,4,1,18,5,8,3,2,1,20,1,2,9,32,5,
%U A094521 22,1,4,3,10,1,24,1,2,25,4,11,6,1,16,27,2,1,12,5,2,3,8,1,30,7,4,3,2,5,32,1
%N A094521 a(n) = gcd(n, A094457(n)).
%H A094521 Michael De Vlieger, <a href="/A094521/b094521.txt">Table of n, a(n) for n = 2..10000</a>
%e A094521 a(18) = gcd(18,12) = 6.
%t A094521 f[n_] := Block[{g, h}, g[x_] := Flatten[Table[#1, {#2}] & @@@ FactorInteger@ x]; h[x_] := If[x == 2, 1, NextPrime[x, -1]]; If[n == 1, 1, Max[Times @@ MapAt[h, g[n], #] & /@ Range[Length@ g[n]]]]]; Table[GCD[i, f@ i], {i, 2, 74}] (* _Michael De Vlieger_, Jan 31 2015 *)
%Y A094521 Cf. A094457 A094522.
%K A094521 easy,nonn
%O A094521 2,3
%A A094521 _Marc LeBrun_, May 06 2004