A378934 Number of minimal edge cuts in the 4 X n grid graph.

3, 28, 146, 627, 2471, 9292, 33878, 120771, 423251, 1463908, 5011690, 17021179, 57450167, 192966908, 645696454, 2154226075, 7170606795, 23825657596, 79055534746, 262031761435, 867792229799, 2872103661988, 9501035284286, 31417942222787, 103862506390523, 343276150243020

Offset

1,1

Links

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

Index entries for linear recurrences with constant coefficients, signature (10,-37,59,-27,-25,21,5,-4,-1).

Formula

G.f.: x*(3 - 2*x - 23*x^2 + 26*x^3 + 32*x^4 - 2*x^5 - 29*x^6 - 18*x^7 - 3*x^8)/((1 - x)^3*(1 - 2*x - x^2)^2*(1 - 3*x - x^2)).

a(n) = 10*a(n-1) - 37*a(n-2) + 59*a(n-3) - 27*a(n-4) - 25*a(n-5) + 21*a(n-6) + 5*a(n-7) - 4*a(n-8) - a(n-9) for n >= 10.

a(n) = A166766(n)/2.

Crossrefs

Row 4 of A378932.

Cf. A166766, A378933.

Sequence in context: A048367 A095665 A145346 * A184440 A012762 A012778

Adjacent sequences: A378931 A378932 A378933 * A378935 A378936 A378937

Keyword

nonn

Author

Andrew Howroyd, Dec 11 2024

Status

approved