OFFSET
1,2
COMMENTS
Also known as fixed polyplets. - David Bevan, Jul 28 2009
REFERENCES
D. H. Redelmeier, personal communication.
N. J. A. Sloane and Simon Plouffe, The Encyclopedia of Integer Sequences, Academic Press, 1995 (includes this sequence).
LINKS
M. F. Hasler, Illustration of the A006770(3)=20 fixed 3-polyplets, Sep 29 2014.
S. Mertens, Lattice animals: a fast enumeration algorithm and new perimeter polynomials, J. Stat. Phys. 58 (5-6) (1990) 1095-1108, Table 1.
H. Redelmeier, Emails to N. J. A. Sloane, 1991
Hugo Tremblay and Julien Vernay, On the generation of discrete figures with connectivity constraints, RAIRO-Theor. Inf. Appl. (2024) Vol. 58, Art. No. 16. See p. 13.
Eric Weisstein's World of Mathematics, Polyplet.
Wikipedia, Pseudo polyomino
EXAMPLE
a(2)=4: the two fixed dominoes and the two rotations of the polyplet consisting of two cells touching at a vertex. - David Bevan, Jul 28 2009
a(3)=20 counts 4 rotations (by 0°, 45°, 90°, 135°) of the straight ... trinomino, and 8 rotations (by multiples of 45°) of the L-shaped .: trinomino and the ..· 3-polyplet, cf. link to the image. - M. F. Hasler, Sep 30 2014
CROSSREFS
KEYWORD
nonn,hard,more
AUTHOR
EXTENSIONS
One more term from Joseph Myers, Sep 26 2002
STATUS
approved