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 A030724 #15 Nov 19 2022 10:58:29
%S A030724 3,4,7,21,26,27,33,34,40,47,55,65,82,83,95,96,111,112,114,129,130,132,
%T A030724 138,150,152,159,175,199,200,227,229,239,255,258,259,260,270,271,288,
%U A030724 291,293,303,304,324,329,339,340,345,377,378
%N A030724 Numbers k such that A030717(k) = 2.
%H A030724 Seiichi Manyama, <a href="/A030724/b030724.txt">Table of n, a(n) for n = 1..10000</a>
%H A030724 Michael De Vlieger, <a href="/A030724/a030724.png">Plot a(s(j) + k - 1) at (j,k)</a> for j = 1..512 and s = partial sums of A030719, showing a(m) = 2 in red and a(m) != 2 in light blue.
%t A030724 nn = 30; m = 2; c[_] = 0; k = a[1] = c[1] = 1; Reap[Do[w = Union@ Array[a, k]; Do[Set[a[j + k], c[w[[j]]]]; If[a[j + k] == m, Sow[m]], {j, Length[w]}]; Do[c[a[j + k]]++, {j, Length[w]}]; k += Length[w], {n, nn}] ][[-1, -1]] (* _Michael De Vlieger_, Nov 19 2022 *)
%Y A030724 Cf. A030723, A030725, A030726.
%Y A030724 Cf. A030717.
%K A030724 nonn
%O A030724 1,1
%A A030724 _Clark Kimberling_