A348663 Number of tree polyominoes with width 3 and height n.

1, 10, 55, 243, 980, 3789, 14357, 53832, 200723, 746163, 2769272, 10268745, 38059769, 141027852, 522497759, 1935672399, 7170707492, 26563347645, 98400786941, 364511817696, 1350277982987, 5001888029643, 18528672997520, 68636390514801, 254252031427649, 941833988656500, 3488865685348919

Offset

1,2

Links

Table of n, a(n) for n=1..27.

Maxime Samson, Valence de graphes et polyominos arbres, Mémoire, Trois-Rivières, Université du Québec à Trois-Rivières, 152 p., 2020.

Index entries for linear recurrences with constant coefficients, signature (8,-21,15,34,-101,120,-66,12).

Formula

G.f.: x*(1 + 2*x - 4*x^2 - 2*x^3 + 7*x^4 - 12*x^5 + 4*x^7)/((1 - x)(1 - 2*x)(1 - 5*x + 4*x^2 + 7*x^3 - 21*x^4 + 24*x^5 - 6*x^6)).

Crossrefs

Cf. A348707.

Sequence in context: A249460 A022575 A202481 * A169720 A024210 A253002

Adjacent sequences: A348660 A348661 A348662 * A348664 A348665 A348666

Keyword

nonn,easy

Author

Maxime Samson, Oct 30 2021

Status

approved