OFFSET
1,2
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
CROSSREFS
KEYWORD
nonn
AUTHOR
STATUS
approved