A246148 Number of inequivalent n X 3 binary matrices, where equivalence means permutations of rows or columns or the symbol set.

1, 2, 8, 18, 47, 95, 200, 367, 674, 1142, 1914, 3040, 4765, 7189, 10702, 15487, 22135, 30949, 42794, 58143, 78216, 103723, 136338, 177081, 228201, 291119, 368790, 463149, 578011, 715946, 881810, 1078952, 1313462, 1589639, 1915028, 2295059, 2738985, 3253576

Offset: 0

Author

Alois P. Heinz, Aug 17 2014

Keywords

• nonn
• easy

Links

• Alois P. Heinz, Table of n, a(n) for n = 0..1000
• Index to number of inequivalent matrices modulo permutation of rows and columns

Crossrefs

Column k=3 of A242093.

Programs

Maple

a:= n-> coeff(series((x^10-x^9+2*x^8+x^7+4*x^6-2*x^5
        +4*x^4+x^3+2*x^2-x+1)/((x^2-x+1) *(x^2+x+1)^2
        *(x+1)^4 *(x-1)^8), x, n+1), x, n):
seq(a(n), n=0..50);

Formula

G.f.: (x^10 -x^9 +2*x^8 +x^7 +4*x^6 -2*x^5 +4*x^4 +x^3 +2*x^2 -x +1)/ ((x^2-x+1) *(x^2+x+1)^2 *(x+1)^4 *(x-1)^8).