A292074 Number of minimum dominating sets in the n X n rook complement graph.
1, 4, 48, 240, 1000, 3300, 9114, 21952, 47520, 94500, 175450, 307824, 515112, 828100, 1286250, 1939200, 2848384, 4088772, 5750730, 7942000, 10789800, 14443044, 19074682, 24884160, 32100000, 40982500, 51826554, 64964592, 80769640, 99658500, 122095050
Offset: 1
Links
- Andrew Howroyd, Table of n, a(n) for n = 1..200
- Eric Weisstein's World of Mathematics, Minimum Dominating Set
- Eric Weisstein's World of Mathematics, Rook Complement Graph
- Index entries for linear recurrences with constant coefficients, signature (7,-21,35,-35,21,-7,1).
Programs
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Mathematica
Join[{1, 4, 48}, LinearRecurrence[{7, -21, 35, -35, 21, -7, 1}, {240, 1000, 3300, 9114, 21952, 47520, 94500}, 20]] Table[Piecewise[{{1, n == 1}, {48, n == 3}}, 6 Binomial[n, 3]^2 + n^2 (n - 1)^2], {n, 20}] CoefficientList[Series[(-1 + 3 x - 41 x^2 + 47 x^3 - 223 x^4 + 221 x^5 - 217 x^6 + 127 x^7 - 42 x^8 + 6 x^9)/(-1 + x)^7, {x, 0, 20}], x]
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PARI
a(n) = if(n<4, [1,4,48][n], 6*binomial(n, 3)^2 + n^2*(n-1)^2); \\ Andrew Howroyd, Sep 13 2017
Formula
G.f.: x*(-1 + 3*x - 41*x^2 + 47*x^3 - 223*x^4 + 221*x^5 - 217*x^6 + 127*x^7 - 42*x^8 + 6*x^9)/(-1 + x)^7.
a(n) = 7*a(n-1) - 21*a(n-2) + 35*a(n-3) - 35*a(n-4) + 21*a(n-5) - 7*a(n-6) + a(n-7) for n > 10.
a(n) = 6*binomial(n, 3)^2 + n^2*(n-1)^2 for n > 3. - Andrew Howroyd, Sep 13 2017
Extensions
Terms a(6) and beyond from Andrew Howroyd, Sep 13 2017
Comments