Comment on A71879
Roland Bacher
Roland.Bacher at ujf-grenoble.fr
Mon Sep 24 19:09:16 CEST 2007
Dear Sequence-fans,
sequence A71879 has the following cryptic comment by E Deutsch which
I do not understand.:
COMMENT
Number of ordered trees with n edges and having nonleaf nodes
of outdegree 0 or 1. -
Emeric Deutsch (deutsch(AT)duke.poly.edu), Nov 03 2002
I tried to contact him without success.
Has anybody a clue?
My problems origin mainly in the expression "non-leaf nodes of
outdegree 0": these are leaves or I am an idiot (of course, both
statements are possibly true but one of them should not be false).
Roland Bacher
A071879 Coefficients of power series solution to g(x) = 1 + x*g(x) + (x*g(x))^3. The first-order differences of these coefficients of g(x), where: g(x) = 1 + 1x + 1x^2 + 2x^3 + 5x^4 + 11x^5 + 24x^6 + ... + a(n)*x^n + ..., forms the coefficients of the third power of g(x), where: g(x)^3 = 1 + 3x + 6x^2 + 13x^3 + 33x^4 + 84x^5 + 208x^6 + 522x^7 + ... +20
2
1, 1, 1, 2, 5, 11, 24, 57, 141, 349, 871, 2212, 5688, 14730, 38403, 100829, 266333, 706997, 1885165, 5047522, 13565203, 36578497, 98934826, 268342933, 729709432, 1989021256, 5433518806, 14873285506, 40790118487, 112064912455 (list; graph; listen)
OFFSET
0,4
COMMENT
Number of ordered trees with n edges and having nonleaf nodes of outdegree 0 or 1. - Emeric Deutsch (deutsch(AT)duke.poly.edu), Nov 03 2002
G.f. (offset 1) is series reversion of x^2/(x+x^2+x^4).
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