OFFSET
0,2
LINKS
B. N. Cyvin et al., Isomer enumeration of unbranched catacondensed polygonal systems with pentagons and heptagons, Match, No. 34 (Oct 1996), pp. 109-121.
FORMULA
G.f.: 1/(1 - 6*x - 2*x*y). - Ilya Gutkovskiy, Apr 21 2017
MATHEMATICA
Table[Binomial[n, k]6^(n-k) 2^k, {n, 0, 10}, {k, 0, n}]//Flatten (* Harvey P. Dale, Aug 01 2021 *)
CROSSREFS
KEYWORD
AUTHOR
STATUS
approved