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

1,4

Links

Table of n, a(n) for n=1..28.

N. J. A. Sloane, Transforms

Formula

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

Mathematica

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

Crossrefs

Cf. A030266.

Sequence in context: A272484 A253409 A027412 * A149831 A149832 A229046

Adjacent sequences: A030274 A030275 A030276 * A030278 A030279 A030280

Keyword

nonn,eigen

Author

Christian G. Bower

Status

approved