A036656 Number of n-node rooted unlabeled trees with outdegree <= 2 and exactly 1 edge at the root.

0, 0, 1, 1, 2, 3, 6, 11, 23, 46, 98, 207, 451, 983, 2179, 4850, 10905, 24631, 56011, 127912, 293547, 676157, 1563372, 3626149, 8436379, 19680277, 46026618, 107890609, 253450711, 596572387, 1406818759, 3323236238, 7862958391

Offset

0,5

Links

Table of n, a(n) for n=0..32.

Index entries for sequences related to rooted trees

Maple

G036656 := G001190-x; A036656 := n->coeff(G036656, x, n);

Mathematica

terms = 33; A[_] = 0; Do[A[x_] = x + (1/2)*(A[x]^2 + A[x^2]) + O[x]^terms // Normal, terms];
CoefficientList[A[x] - x, x] (* Jean-François Alcover, Jan 24 2018 *)

Crossrefs

Except for initial terms, same as A001190.

Sequence in context: A036591 A365821 A036592 * A001190 A274937 A359392

Adjacent sequences: A036653 A036654 A036655 * A036657 A036658 A036659

Keyword

nonn

Author

N. J. A. Sloane

Status

approved