A378937 Number of minimal edge cuts in the 2 X n rook graph.

1, 6, 22, 84, 346, 1476, 6322, 26844, 112666, 467796, 1925122, 7867404, 31980586, 129475716, 522603922, 2104600764, 8461122106, 33972973236, 136278002722, 546271650924, 2188568145226, 8764722448356, 35090249881522, 140455100761884, 562102748697946, 2249258115629076

Offset

1,2

Links

Andrew Howroyd, Table of n, a(n) for n = 1..1000

Index entries for linear recurrences with constant coefficients, signature (10,-35,50,-24).

Formula

a(n) = A134165(n) - 2.

a(n) = 2^(2*n-1) - 3^n + 5*2^(n-1) - 3.

G.f.: (1 - 4*x - 3*x^2 + 24*x^3)/((1 - x)*(1 - 2*x)*(1 - 3*x)*(1 - 4*x)).

E.g.f.: exp(x)*(2*exp(3*x) - 3*exp(2*x) + 5*exp(x) - 3). - Stefano Spezia, Mar 03 2025

Mathematica

LinearRecurrence[{10, -35, 50, -24}, {1, 6, 22, 84}, 30] (* Paolo Xausa, Mar 02 2025 *)

Prog

(PARI) a(n) = 2^(2*n-1) - 3^n + 5*2^(n-1) - 3

Crossrefs

Row 2 of A378935.

Cf. A134165.

Sequence in context: A253070 A255461 A003699 * A047124 A046365 A266184

Adjacent sequences: A378934 A378935 A378936 * A378938 A378939 A378940

Keyword

nonn,easy,changed

Author

Andrew Howroyd, Dec 12 2024

Status

approved