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, Nov 18 2025: (Start)
a(n) = - 2*a(n-2) + a(n-3) - 3*a(n-4) + 3*a(n-5) - 3*a(n-6) + 5*a(n-7) - 4*a(n-8) + 6*a(n-9) - 4*a(n-10) + 6*a(n-11) - 4*a(n-12) + 5*a(n-13) - 3*a(n-14) + 3*a(n-15) - 3*a(n-16) + a(n-17) - 2*a(n-18) - a(n-20) for n > 20.
G.f.: (x^20 + 6*x^19 + 11*x^18 + 28*x^17 + 35*x^16 + 64*x^15 + 67*x^14 + 102*x^13 + 91*x^12 + 126*x^11 + 100*x^10 + 126*x^9 + 91*x^8 + 102*x^7 + 67*x^6 + 64*x^5 + 35*x^4 + 28*x^3 + 11*x^2 + 6*x + 1)/((x - 1)^2*(x^2 - x + 1)*(x^2 + x + 1)^2*(x^4 - x^3 + x^2 - x + 1)*(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
