%I #22 May 01 2023 15:01:13
%S 6,146,1618,14248,111030,801756,5493524,36213404,231727206,1448346368,
%T 8882264970,53630707124,319658314238,1884696886358,11010327107946,
%U 63818465537674,367417387464528,2102996368589366,11976130801913690,67900925937645280,383491738397537356
%N Number of (undirected) paths in the grid graph P_4 X P_n.
%H Andrew Howroyd, <a href="/A358800/b358800.txt">Table of n, a(n) for n = 1..200</a>
%H <a href="/index/Rec#order_20">Index entries for linear recurrences with constant coefficients</a>, signature (27,-318,2162,-9476,28327,-59457,88270,-90466, 57194,-9664,-20392, 21783,-8809,-724,2316,-732,-135,99,0,-4).
%F G.f.: x*(6 - 16*x - 416*x^2 + 4018*x^3 - 17938*x^4 + 50228*x^5 - 97356*x^6 + 131868*x^7 - 116556*x^8 + 55784*x^9 - 2296*x^10 - 18094*x^11 + 20784*x^12 - 12882*x^13 + 1542*x^14 + 1748*x^15 - 430*x^16 - 4*x^17 - 24*x^18 - 2*x^19 + 4*x^20)/((1 - x)^2*(1 - 3*x + x^2)*(1 - 7*x + 12*x^2 - 7*x^3 + 3*x^4 + 2*x^5)^2*(1 - 8*x + 15*x^2 - 5*x^3 - 9*x^4 + 2*x^5 + x^6)). - _Andrew Howroyd_, Jan 27 2023
%Y Row 4 of A288518.
%K nonn,easy
%O 1,1
%A _Seiichi Manyama_, Dec 01 2022
%E Terms a(14) and beyond from _Andrew Howroyd_, Jan 27 2023