A332753 G.f. A(x) satisfies: A(x) = x * (1 + A(x) + A(x^2)^2 + A(x^3)^3 + ...).

1, 1, 1, 1, 2, 2, 4, 4, 7, 8, 12, 12, 22, 22, 32, 38, 56, 56, 90, 90, 132, 150, 204, 204, 326, 327, 437, 489, 677, 677, 994, 994, 1361, 1499, 1943, 1958, 2889, 2889, 3733, 4078, 5445, 5445, 7549, 7549, 9969, 10853, 13733, 13733, 19329, 19330, 24577, 26404, 34080

Offset: 1

Author

Ilya Gutkovskiy, Feb 22 2020

Keywords

• nonn

Comments

If n is prime or 1 then a(n) = a(n+1).

Crossrefs

Cf. A000108, A003238, A008578, A038046.

Programs

Mathematica

terms = 53; A[] = 0; Do[A[x] = x (1 + Sum[A[x^k]^k, {k, 1, terms}]) + O[x]^(terms + 1) // Normal, terms + 1]; CoefficientList[A[x], x] // Rest