A358709 - OEIS

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A358709

a(n) is the number of free, tree-like polyiamonds, of size 3*n+1, with 120-degree rotational symmetry formed of a central triangle and identical, non-intersecting snakes leading from each of its sides.

1

1, 1, 1, 2, 3, 6, 11, 20, 37, 66, 119, 217, 391, 706, 1274, 2289, 4133, 7435, 13384, 24068

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

OFFSET

0,4

LINKS

Table of n, a(n) for n=0..19.

John Mason, Illustrations

CROSSREFS

Sequence in context: A010033 A065615 A054182 * A346736 A335628 A355560

Adjacent sequences: A358706 A358707 A358708 * A358710 A358711 A358712

KEYWORD

nonn,more

AUTHOR

John Mason, Jan 10 2023

STATUS

approved