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A036656
Number of n-node rooted unlabeled trees with outdegree <= 2 and exactly 1 edge at the root.
7
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
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
KEYWORD
nonn
STATUS
approved