0,8

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.

Index entries for sequences related to trees

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

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

Sequence in context: A149341 A149342 A149343 this_sequence A017942 A149344 A135489

Adjacent sequences: A052300 A052301 A052302 this_sequence A052304 A052305 A052306

nonn

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