A060336 Number of n X n {-1,0,1} matrices modulo rows permutation (by symmetry this is the same as the number of {-1,0,1} matrices modulo columns permutation), i.e., the number of equivalence classes where two matrices A and B are equivalent if one of them is the result of permuting the rows of the other.

3, 45, 3654, 1929501, 7355513529, 212787633478239, 47937678641708357304, 85524882506287709213421693, 1224201212028616655577478516173315, 142132497715474639139076246298436794277130

Offset

1,1

Links

Harry J. Smith, Table of n, a(n) for n = 1..47

Formula

a(n) = C(3^n + n - 1, n) (where C(n, k) denotes the binomial coefficient).

a(n) ~ 3^(n^2) / n!. - Vaclav Kotesovec, Jul 02 2016

Mathematica

Table[Binomial[3^n+n-1, n], {n, 10}] (* Harvey P. Dale, Apr 10 2012 *)

Prog

(PARI) { for (n=1, 47, write("b060336.txt", n, " ", binomial(3^n + n - 1, n)); ) } \\ Harry J. Smith, Jul 03 2009

Crossrefs

A060690.

Sequence in context: A099168 A227379 A004105 * A268196 A057863 A302156

Adjacent sequences: A060333 A060334 A060335 * A060337 A060338 A060339

Keyword

nonn

Author

Ahmed Fares (ahmedfares(AT)my-deja.com), Apr 25 2001

Extensions

More terms from Harry J. Smith, Jul 03 2009

Status

approved