A360195 Number of acyclic spanning subgraphs in the 4 X n grid graph.

8, 836, 85818, 8790016, 900013270, 92146956300, 9434262852690, 965904015750408, 98891686243392270, 10124779093041746052, 1036600283636692454794, 106129737227642833341248, 10865828704552798371380934, 1112470797598979236296844092, 113897550673086022197853291458

Offset: 1

Author

Andrew Howroyd, Jan 29 2023

Keywords

• nonn
• easy

Links

• Andrew Howroyd, Table of n, a(n) for n = 1..200
• Index entries for linear recurrences with constant coefficients, signature (146,-5145,74504,-525120,1885344,-3430128,3147392,-1418496,278528,-16384).

Crossrefs

Row 4 of A360194.

Cf. A003696, A359991.

Formula

G.f.: x*(8 - 332*x + 4922*x^2 - 34224*x^3 + 120160*x^4 - 215504*x^5 + 196576*x^6 - 88512*x^7 + 17408*x^8 - 1024*x^9)/(1 - 146*x + 5145*x^2 - 74504*x^3 + 525120*x^4 - 1885344*x^5 + 3430128*x^6 - 3147392*x^7 + 1418496*x^8 - 278528*x^9 + 16384*x^10).