A001170 Number of board-pair-pile polyominoes with n cells.

1, 2, 6, 19, 63, 216, 760, 2723, 9880, 36168, 133237, 492993, 1829670, 6804267, 25336611, 94416842, 351989967, 1312471879, 4894023222, 18248301701, 68036380665, 253638655582, 945464013411, 3523978989671, 13133649924269

Offset: 1

Author

N. J. A. Sloane

Keywords

• nonn

References

• W. F. Lunnon, Counting polyominoes, pp. 347-372 of A. O. L. Atkin and B. J. Birch, editors, Computers in Number Theory. Academic Press, NY, 1971.
• N. J. A. Sloane, A Handbook of Integer Sequences, Academic Press, 1973 (includes this sequence).
• N. J. A. Sloane and Simon Plouffe, The Encyclopedia of Integer Sequences, Academic Press, 1995 (includes this sequence).

Links

• Vaclav Kotesovec, Table of n, a(n) for n = 1..54 (computed by Doron Zeilberger)
• Moa Apagodu, Counting hexagonal lattice animals, arXiv:math/0202295 [math.CO], 2002-2009.
• D. Zeilberger, The umbral transfer-matrix method. III. Counting animals, New York J. Math 7 (2001) 223-231