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 A349261 #8 Mar 09 2022 09:33:43
%S A349261 2,14,125,135,2079,21735,2730375,916352,5955200,4122495,444741759,
%T A349261 7391633535,98228219264
%N A349261 a(n) is the least number k such that A349258(k) = A349258(k+1) = n.
%e A349261 2 is a term since A349258(2) = A349258(3) = 1.
%e A349261 14 is a term since A349258(14) = A349258(15) = 2.
%t A349261 f[p_, e_] := 2^DigitCount[e, 2, 1] - 1; c[1] = 0; c[n_] := Plus @@ f @@@ FactorInteger[n]; seq[len_, nmax_] := Module[{s = Table[0, {len}], k = 0, n = 1, i}, While[n < nmax && k < len, i = c[n]; If[c[n + 1] == i && i <= len && s[[i]] == 0, k++; s[[i]] = n]; n++]; TakeWhile[s, # > 0 &]]; seq[8, 3*10^6]
%Y A349261 Cf. A349258.
%Y A349261 Similar sequences: A075036, A093548, A115186, A343818.
%K A349261 nonn,more
%O A349261 1,1
%A A349261 _Amiram Eldar_, Nov 12 2021