A030277 Shifts left 2 places under COMPOSE transform.

1, 1, 1, 2, 4, 10, 28, 86, 286, 1019, 3857, 15418, 64782, 285041, 1309355, 6263085, 31127475, 160432093, 856039863, 4721638083, 26883787141, 157812750656, 953995201996, 5932516347277, 37913110456751, 248768719522450, 1674488577654500, 11553041105489900

Offset: 1

Author

Christian G. Bower

Keywords

• nonn
• eigen

Links

• N. J. A. Sloane, Transforms

Crossrefs

Cf. A030266.

Programs

Mathematica

Nest[x + x^2 + x^2 (# /. x -> #) &, O[x], 20][[3]] (* Vladimir Reshetnikov, Aug 08 2019 *)

Formula

G.f. A(x) satisfies: A(x) = x + x^2 * (1 + A(A(x))). - Ilya Gutkovskiy, May 10 2019