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 A130336 #20 Sep 23 2021 11:13:04
%S A130336 1,2,7,10,13,22,31,37,58,79,82,94,109,118,157,178,193,214
%N A130336 Record values in A130335.
%F A130336 a(n) = A130335(A130337(n)).
%F A130336 A130335(k) < a(n) for k < A130337(n).
%t A130336 f[n_] := Block[{k = 1}, While[ GCD[n(n + 1)/2, (n + k)(n + k + 1)/2] != 1, k++ ]; k]; t = Table[0, {1000}]; Do[a = f@n; If[a < 1001 && t[[a]] == 0, t[[a]] = n; Print[{a, n}], If[a > 1000, Print[{"Over 1000", n}]]], {n, 2^31 - 1}] (* _Robert G. Wilson v_, Jun 03 2007 *)
%Y A130336 CF. A130335, A130337.
%K A130336 nonn,more
%O A130336 1,2
%A A130336 _Reinhard Zumkeller_, May 28 2007
%E A130336 a(13)-a(16) from _Robert G. Wilson v_, Jun 03 2007
%E A130336 Added a(17) and corrected a(12) by _Chai Wah Wu_, Sep 16 2021
%E A130336 a(18) from _Chai Wah Wu_, Sep 23 2021