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A052303 Number of asymmetric Greg trees. 7
1, 1, 0, 0, 0, 0, 1, 4, 12, 42, 137, 452, 1491, 4994, 16831, 57408, 197400, 685008, 2395310, 8437830, 29917709, 106724174, 382807427, 1380058180, 4998370015, 18181067670, 66393725289, 243347195594, 894959868983, 3301849331598 (list; graph; refs; listen; history; internal format)
OFFSET

0,8

COMMENTS

A Greg tree can be described as a tree with 2-colored nodes where only the black nodes are counted and the white nodes are of degree at least 3.

LINKS

Index entries for sequences related to trees

FORMULA

G.f.: 1+B(x)-B(x)^2 where B(x) is g.f. of A052301.

CROSSREFS

Cf. A005263, A005264, A048159, A048160, A052300-A052302.

Sequence in context: A149341 A149342 A149343 * A017942 A149344 A178078

Adjacent sequences:  A052300 A052301 A052302 * A052304 A052305 A052306

KEYWORD

nonn

AUTHOR

Christian G. Bower (bowerc(AT)usa.net), Nov 15 1999.

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Last modified February 15 21:56 EST 2012. Contains 205860 sequences.