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

0,3

Links

Table of n, a(n) for n=0..31.

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).

Crossrefs

Sequence in context: A214277 A214278 A214279 * A151501 A102735 A088960

Adjacent sequences: A360605 A360606 A360607 * A360609 A360610 A360611

Keyword

nonn,easy

Author

George Spahn, Feb 13 2023

Status

approved