1,3

Table of n, a(n) for n=1..80.

Eric Weisstein's World of Mathematics, Ordered Factorization

a(n) = |{j < n : A074206(j) = A074206(n)}|.

a(14) = 2 because A074206(14) = 3 and also A074206(6) = A074206(10) = 3.

A074206[1] = 1; A074206[n_] := A074206[n] = A074206 /@ Most[Divisors[n]] // Total; Table[Length[Select[Range[n - 1], A074206[#] == A074206[n] &]], {n, 80}]

Cf. A047983, A074206, A338568.

Sequence in context: A352740 A108416 A215395 * A343757 A108760 A343554

Adjacent sequences: A338566 A338567 A338568 * A338570 A338571 A338572

nonn

Ilya Gutkovskiy, Nov 02 2020

approved