A066331 - OEIS

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A066331

Number of fixed hexagonal polyominoes with n cells and tree-like structure.

1

1, 3, 9, 29, 99, 348, 1260, 4644, 17382, 65822, 251655, 969819, 3762517, 14680890, 57567228, 226712655, 896252850, 3555116583, 14144563158

(list; graph; refs; listen; history; text; internal format)

OFFSET

1,2

LINKS

Table of n, a(n) for n=1..19.

Sean A. Irvine, Java program (github)

CROSSREFS

Cf. A001207 (all polyhexes), A038142 (free tree-like).

Sequence in context: A001893 A238979 A151030 * A099780 A006134 A074526

Adjacent sequences: A066328 A066329 A066330 * A066332 A066333 A066334

KEYWORD

nonn,more

AUTHOR

Jan Kristian Haugland, Jan 01 2002

EXTENSIONS

a(16)-a(19) from Sean A. Irvine, Oct 08 2023

STATUS

approved