OFFSET
9,2
LINKS
A. J. Guttmann and A. R. Conway, Hexagonal lattice directed site animals, Statistical Physics on the Eve of the Twenty-First Century, ed. M. T. Batchelor, World Scientific, 1999 (H_9 for hexagonal lattices Table 1).
FORMULA
G.f.: x^9*B(x)/((1-x)^19*(1+x)^9*(1+x^2)^8*(1+x^2+x^4)^6*(1+x^4)^4*(1+x^2+x^4+x^6+x^8)^2) where B(x) is g.f. of A055918.
CROSSREFS
KEYWORD
nonn
AUTHOR
Christian G. Bower, Jun 22 2000
EXTENSIONS
a(31) corrected and more terms from Sean A. Irvine, Apr 09 2022
STATUS
approved