OFFSET
0,4
COMMENTS
Or, number of 2-sided snake polyominoes with n cells. - Ed Pegg Jr, May 13 2009
REFERENCES
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).
R. C. Tilley, R. G. Stanton and D. D. Cowan, The cell growth problem for filaments, pp. 310-339 in Proceedings of the Louisiana Conference on Combinatorics, Graph Theory and Computer Science. Vol. 1, edited R. C. Mullin et al., 1970.
LINKS
Arthur O'Dwyer, Polyomino strips, snakes, and ouroboroi, Dec 10 2022.
Ed Pegg, Jr., Illustrations of polyforms
Herman Tulleken, Polyominoes 2.2: How they fit together, (2019).
Eric Weisstein's World of Mathematics, Polyomino
CROSSREFS
KEYWORD
nonn
AUTHOR
EXTENSIONS
a(23) from Joseph Myers, Nov 22 2010
a(24)-a(26) from Sean A. Irvine, May 21 2013
a(27)-a(32) from John Mason, Dec 05 2021
STATUS
approved