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A106363 Planar trees where no branch is identical to its adjacent neighbor. 2
1, 1, 0, 1, 0, 1, 3, 7, 14, 43, 115, 326, 931, 2719, 7979, 23804, 71418, 216444, 660276, 2028558, 6268350, 19479746, 60835542, 190881085, 601459251, 1902680249, 6040955223, 19245061851, 61503863732, 197135868680, 633615135842 (list; graph; refs; listen; history; text; internal format)
OFFSET

1,7

LINKS

Table of n, a(n) for n=1..31.

Index entries for sequences related to trees

FORMULA

G.f.: A(x) = B(x) + (C(x^2) - C(x)^2)/2. B(x) is g.f. of A106362. C(x) is g.f. of A106361.

CROSSREFS

Cf. A002995.

Sequence in context: A184264 A266019 A146155 * A128658 A234042 A001203

Adjacent sequences:  A106360 A106361 A106362 * A106364 A106365 A106366

KEYWORD

nonn

AUTHOR

Christian G. Bower, Apr 29 2005

STATUS

approved

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Last modified December 4 13:19 EST 2016. Contains 278750 sequences.