A055911 Column 5 of triangle A055907.

1, 10, 56, 240, 854, 2654, 7412, 18974, 45173, 101074, 214361, 433731, 841921, 1574765, 2849215, 5002411, 8546675, 14243335, 23202995, 37016099, 57925111, 89043169, 134635403, 200468817, 294253144, 426179565, 609587498, 861767228

Offset

5,2

Comments

The given generating function does not appear to generate the sequence. - Sean A. Irvine, Apr 09 2022

Links

Table of n, a(n) for n=5..32.

A. J. Guttmann and A. R. Conway, Hexagonal lattice directed site animals, Statistical Physics on the Eve of the Twenty-First Century, ed. M. T. Batchelor, World Scientific, 1999 (H_5 for hexagonal lattices Table 1).

Formula

G.f.: x^5*(1 + 4x + 8x^2 + 22x^3 + 37x^4 + 56x^5 + 88x^6 + 98x^7 + 137x^8 + 118x^9 + 145x^10 + 113x^11 + 104x^12 + 79x^13 + 50x^14 + 40x^15 + 17x^16 + 10x^17 + 6x^18 + x^20) / ((1 - x)^11 * (1 + x)^5 * (1 + x^2)^4 * (1 + x^2 + x^4)^2).

Crossrefs

Cf. A055907.

Sequence in context: A053309 A035040 A002889 * A087076 A014483 A116971

Adjacent sequences: A055908 A055909 A055910 * A055912 A055913 A055914

Keyword

nonn

Author

Christian G. Bower, Jun 15 2000

Status

approved