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