A359987 Number of edge cuts in the n-ladder graph P_2 X P_n.
1, 11, 105, 919, 7713, 63351, 514321, 4148839, 33347041, 267489431, 2143168305, 17160184519, 137349160833, 1099102033911, 8794224638161, 70360221445159, 562911076526881, 4503422288363351, 36027988077717105, 288226686123491719, 2305826176955087553, 18446667292472959671
Offset: 1
Links
- Andrew Howroyd, Table of n, a(n) for n = 1..500
- Eric Weisstein's World of Mathematics, Edge Cut.
- Eric Weisstein's World of Mathematics, Ladder Graph.
- Index entries for linear recurrences with constant coefficients, signature (13,-42,16).
Crossrefs
Programs
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Mathematica
LinearRecurrence[{13, -42, 16}, {1, 11, 105}, 25] (* Paolo Xausa, Jun 24 2024 *) Table[2^(3 n - 2) + (((5 - Sqrt[17])/2)^n - ((5 + Sqrt[17])/2)^n)/Sqrt[17], {n, 20}] // Expand (* Eric W. Weisstein, Nov 03 2024 *) CoefficientList[Series[-(1 - 2 x + 4 x^2)/((-1 + 8 x) (1 - 5 x + 2 x^2)), {x, 0, 20}], x] (* Eric W. Weisstein, Nov 03 2024 *) -
PARI
Vec((1 - 2*x + 4*x^2)/((1 - 8*x)*(1 - 5*x + 2*x^2)) + O(x^25))