A052267 Number of 2 X n matrices over GF(3) under row and column permutations.

1, 6, 27, 92, 267, 678, 1561, 3312, 6582, 12372, 22194, 38232, 63594, 102564, 160974, 246576, 369567, 543114, 784069, 1113684, 1558557, 2151578, 2933151, 3952416, 5268796, 6953544, 9091668, 11783856, 15148836, 19325736, 24476940, 30790944, 38485773, 47812398

Offset

0,2

Links

Colin Barker, Table of n, a(n) for n = 0..1000

Index entries for linear recurrences with constant coefficients, signature (6,-12,2,27,-36,0,36,-27,-2,12,-6,1).

Formula

G.f.: (3*x^2+1) /((1-x^2)^3*(1-x)^6).

a(n) = ((315*(475+37*(-1)^n) + 6*(54959+945*(-1)^n)*n + (298618+630*(-1)^n)*n^2 + 150528*n^3 + 46788*n^4 + 9156*n^5 + 1092*n^6 + 72*n^7 + 2*n^8)) / 161280. - Colin Barker, Jan 16 2017

Prog

(PARI) Vec((3*x^2+1) / ((1-x^2)^3*(1-x)^6) + O(x^40)) \\ Colin Barker, Jan 16 2017

Crossrefs

Cf. A002623, A002727.

Sequence in context: A131985 A125196 A100189 * A038166 A327384 A121596

Adjacent sequences: A052264 A052265 A052266 * A052268 A052269 A052270

Keyword

nonn,easy

Author

Vladeta Jovovic, Feb 04 2000

Status

approved