A121120 Related to enumeration of free catapolyoctagons (see Cyvin reference for precise definition).

1, 1, 6, 32, 245, 1926, 16119, 137475, 1194854, 10517058, 93593287, 840500847, 7607643154, 69331324533, 635651786601, 5858956542866, 54260363841729, 504655054951887, 4711672806323948, 44143665936691049, 414896145593829741, 3910842418588639201

Offset

1,3

References

S. J. Cyvin, B. N. Cyvin, and J. Brunvoll. Enumeration of tree-like octagonal systems: catapolyoctagons, ACH Models in Chem. 134 (1997), 55-70, Tbale IV, P_r.

Links

Table of n, a(n) for n=1..22.

Formula

8*a(n) = 2*A036758(n) -7*A036758(n-1)+4*A036758((n-1)/2)+2*A036758((n-1) +4*A036759(n)-2*A036759(n-1) +A121115(n)-7*A121115(n-1)+3*A121115((n-1)/2) +2*A121118(n) [Cyvin eq (46)] where A(.) is zero for fractional indices. - R. J. Mathar, Jul 31 2019

Crossrefs

Sequence in context: A283326 A221540 A331878 * A183681 A326985 A350485

Adjacent sequences: A121117 A121118 A121119 * A121121 A121122 A121123

Keyword

nonn

Author

N. J. A. Sloane, Aug 13, 2006

Status

approved