A253927 Number of polyhexes (without holes) of size 6*n+1 with 6-fold rotational symmetry.

1, 1, 2, 4, 11, 37, 136, 540, 2229, 9505

Offset

0,3

Links

Table of n, a(n) for n=0..9.

Björg N. Cyvin, Jon Brunvoll and Sven J. Cyvin, Enumeration of benzenoid systems and other polyhexes, p. 65-180 in: I. Gutman (ed.), Advances in the Theory of Benzenoid Hydrocarbons II, Springer, 1992.

S. J. Cyvin, J. Brunvoll, and B. N. Cyvin, Topological aspects of benzenoids and coronoids, including "snowflakes" and "laceflowers", Computers & Mathematics with Applications, vol. 17, no. 1-3, pp. 355-374, (1989); see table 1 on p. 361.

S. J. Cyvin, B. N. Cyvin, and J. Brunvoll, Benzenoids with hexagonal symmetry, including the rare animals "all-flakes", Journal of Molecular Structure, vol. 198, pp. 31-49, (July 1989); see p. 32 for images of all such polyhexes for 6*n+1 <= 37.

Crossrefs

Sequence in context: A035098 A328425 A174107 * A281481 A138301 A367495

Adjacent sequences: A253924 A253925 A253926 * A253928 A253929 A253930

Keyword

nonn,hard,more

Author

Joerg Arndt, Jan 19 2015

Extensions

a(7)-a(9) from Cyvin, Brunvoll & Cyvin 1992 (Table 31) added by Andrey Zabolotskiy, Feb 16 2023

Status

approved