OFFSET
1,2
LINKS
Nico Van Cleemput, Table of n, a(n) for n = 1..75
Gunnar Brinkmann and Nico Van Cleemput, Classification and generation of nanocones, Discrete Applied Mathematics, 159 (2011), 1528-1539.
FORMULA
Conjectured g.f.: (x^7 + x^5 + x^4 + 2*x^3 + 2*x + 1)*x/((x - 1)^4*(x + 1)^2*(x^2 + x + 1)). [D. S. McNeil, Oct 20 2011]
CROSSREFS
KEYWORD
nonn
AUTHOR
Nico Van Cleemput, Oct 20 2011
STATUS
approved