OFFSET
5,1
LINKS
Andrew Howroyd, Table of n, a(n) for n = 5..500
P. Lisonek, Closed forms for the number of polygon dissections, Journal of Symbolic Computation 20 (1995), 595-601.
Ronald C. Read, On general dissections of a polygon, Aequat. math. 18 (1978) 370-388.
FORMULA
Conjectures from Colin Barker, Nov 25 2017: (Start)
G.f.: x^5*(3 + 5*x - x^2 - x^3) / ((1 - x)^4*(1 + x)^2).
a(n) = (n-4)*(-5 + (-1)^n - 4*n + 2*n^2) / 8 for n>4.
a(n) = 2*a(n-1) + a(n-2) - 4*a(n-3) + a(n-4) + 2*a(n-5) - a(n-6) for n>10.
(End)
a(n) = Sum_{k=0..n-5} f(k), where f(n) = Sum_{k=0..n} 3 + lcm(k, 2)) (conjecture). - Jon Maiga, Nov 28 2018
PROG
(PARI) \\ See A003442 for DissectionsModCyclicRooted()
{ my(v=DissectionsModCyclicRooted(apply(i->y + O(y^4), [1..40]))); apply(p->polcoeff(p, 3), v[5..#v]) }
CROSSREFS
KEYWORD
nonn
AUTHOR
Andrew Howroyd, Nov 24 2017
STATUS
approved