A359991 Number of connected spanning subgraphs in the 4 X n grid graph.

1, 105, 7857, 555195, 38757695, 2698167665, 187715481077, 13057666054455, 908271228919067, 63177423571626685, 4394479113198329137, 305669914361091938915, 21261697652022553831895, 1478914849135091196256585, 102869919107895518546358701

Offset

1,2

Links

Andrew Howroyd, Table of n, a(n) for n = 1..200

Index entries for linear recurrences with constant coefficients, signature (105,-2907,33255,-183316,519800,-778624,610800,-237312,39680,-2048).

Formula

G.f.: x*(1 - 261*x^2 + 2190*x^3 - 5940*x^4 + 5400*x^5 - 672*x^6 - 960*x^7 + 256*x^8)/(1 - 105*x + 2907*x^2 - 33255*x^3 + 183316*x^4 - 519800*x^5 + 778624*x^6 - 610800*x^7 + 237312*x^8 - 39680*x^9 + 2048*x^10).

Crossrefs

Row 4 of A359993.

Sequence in context: A168306 A075914 A075924 * A199353 A263888 A269474

Adjacent sequences: A359988 A359989 A359990 * A359992 A359993 A359994

Keyword

nonn,easy

Author

Andrew Howroyd, Jan 28 2023

Status

approved