OFFSET
0,2
COMMENTS
Note that there may be other vertices in the Galebach list of u-uniform tilings with u <= 6 that have this same coordination sequence. See the Galebach link for the complete list of A-numbers for all these tilings.
LINKS
FORMULA
Conjectures from Chai Wah Wu, Jan 24 2020: (Start)
a(n) = - a(n-2) - a(n-4) - a(n-6) + 2*a(n-7) + 2*a(n-9) + 2*a(n-11) + 2*a(n-13) - a(n-14) - a(n-16) - a(n-18) - a(n-20) for n > 20.
G.f.: (x^20 + 4*x^19 + 9*x^18 + 17*x^17 + 26*x^16 + 38*x^15 + 53*x^14 + 68*x^13 + 80*x^12 + 86*x^11 + 89*x^10 + 86*x^9 + 80*x^8 + 68*x^7 + 53*x^6 + 38*x^5 + 26*x^4 + 16*x^3 + 9*x^2 + 4*x + 1)/((x - 1)^2*(x^2 + 1)*(x^4 + 1)*(x^6 + x^5 + x^4 + x^3 + x^2 + x + 1)^2). (End)
CROSSREFS
KEYWORD
nonn
AUTHOR
Brian Galebach and N. J. A. Sloane, Jun 18 2018
STATUS
approved