A360608 Number of solutions to a 4 X n Ring-Ring puzzle on an empty grid.
1, 0, 2, 1, 8, 12, 45, 98, 292, 725, 2004, 5210, 14051, 37126, 99336, 263991, 704622, 1876566, 5005327, 13341292, 35579622, 94866875, 252998042, 674677856, 1799331865, 4798687520, 12798199466, 34133165825, 91035612400, 242799614636, 647572193925, 1727149489058
Offset: 0
Links
- George Spahn, Enumerating solutions to grid based puzzles with a fixed number of rows, arXiv:2202.06234 [math.CO], Feb 2022.
- Index entries for linear recurrences with constant coefficients, signature (3,3,-10,-3,5,1).
Formula
G.f.: -(2*x^2 + x - 1)*(x^2 + 2*x - 1)/(x^6 + 5*x^5 - 3*x^4 - 10*x^3 + 3*x^2 + 3*x - 1).