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 A338568 #6 Feb 16 2025 08:34:00
%S A338568 0,1,2,0,3,1,4,0,2,3,5,0,6,4,5,0,7,1,8,2,6,7,9,0,8,9,1,3,10,1,11,1,10,
%T A338568 11,12,0,12,13,14,2,13,2,14,4,5,15,15,0,16,6,17,7,16,3,18,4,19,20,17,
%U A338568 0,18,21,8,1,22,3,19,9,23,4,20,0,21,24,10,11,25,5,22,1
%N A338568 Number of integers less than n with the same number of unordered factorizations as n.
%H A338568 Eric Weisstein's World of Mathematics, <a href="https://mathworld.wolfram.com/UnorderedFactorization.html">Unordered Factorization</a>
%F A338568 a(n) = |{j < n : A001055(j) = A001055(n)}|.
%e A338568 a(10) = 3 because A001055(10) = 2 and also A001055(4) = A001055(6) = A001055(9) = 2.
%t A338568 T[_, 1] = T[1, _] = 1; T[n_, m_] := T[n, m] = DivisorSum[n, Boole[1 < # <= m] T[n/#, #] &]; A001055[n_] := T[n, n]; Table[Length[Select[Range[n - 1], A001055[#] == A001055[n] &]], {n, 80}]
%Y A338568 Cf. A001055, A330972 (positions of 0's), A338569.
%K A338568 nonn
%O A338568 1,3
%A A338568 _Ilya Gutkovskiy_, Nov 02 2020