A058409 Number of 4 X n nonnegative integer matrices with all column sums 3, up to row and column permutation.

1, 3, 18, 92, 458, 1982, 7928, 28592, 95138, 292993, 845027, 2295322, 5915631, 14535676, 34224682, 77510148, 169459010, 358698558, 737106306, 1473867060, 2873564862, 5472731212, 10198198452, 18621343624, 33361303957, 58713103696

Offset

0,2

Links

Table of n, a(n) for n=0..25.

Vladeta Jovovic, Number of m x l nonnegative integer matrices with all column sums equal to n, up to row and column permutation

Formula

G.f.: 1 / 24*(1 / (1 - x)^20 + 6 / (1 - x)^6 / (1 - x^2)^7 + 3 / (1 - x^2)^10 + 8 / (1 - x)^2 / (1 - x^3)^6 + 6 / (1 - x^4)^5).

Crossrefs

Cf. A050532, A058390, A058407, A058408, A058410.

Sequence in context: A092691 A064671 A363647 * A125833 A129547 A081151

Adjacent sequences: A058406 A058407 A058408 * A058410 A058411 A058412

Keyword

easy,nonn

Author

Vladeta Jovovic, Nov 25 2000

Extensions

More terms from Max Alekseyev, Jun 21 2011

Status

approved