A094165 Number of rooted 2-dimensional polyominoes with n hexagonal cells, with no symmetries removed.

1, 6, 33, 176, 930, 4884, 25564, 133512, 696231, 3626710, 18876363, 98186556, 510472118, 2652899130, 13782560610, 71585293504, 371724613716, 1929911381586, 10018066789546, 51996091023360, 269839578888159, 1400217128810676

Offset

1,2

References

Dan Hoey, Bill Gosper and Richard C. Schroeppel, Discussions in Math-Fun Mailing list, circa Jul 13 1999.

Links

Jean-François Alcover, Table of n, a(n) for n = 1..35

R. C. Schroeppel, A few mathematical experiments, Experimental Mathematics Workshop, Oakland, 2004.

Formula

a(n) = n * A001207(n). - Andrew Howroyd, Dec 04 2018

Mathematica

A001207 = Cases[Import["https://oeis.org/A001207/b001207.txt", "Table"], {_, _}][[All, 2]];
a[n_] := n * A001207[[n]];
Array[a, 22] (* Jean-François Alcover, Sep 08 2019 *)

Crossrefs

A row of A094166.

Cf. A001207.

Sequence in context: A081893 A106850 A284076 * A111994 A092851 A137627

Adjacent sequences: A094162 A094163 A094164 * A094166 A094167 A094168

Keyword

nonn

Author

N. J. A. Sloane, May 07 2004

Status

approved