A377003 - OEIS

A377003

Number of inequivalent 2*n X 6 binary arrays with row sums 3 and column sums n up to row and column permutations.

1, 1, 3, 7, 19, 46, 132, 345, 951, 2457, 6198, 14816, 34126, 75057, 159176, 325021, 642473, 1230711, 2292826, 4160165, 7370620, 12768904, 21671722, 36080204, 59009291, 94910598, 150300578, 234560237, 361082376, 548722631, 823817750

(list; graph; refs; listen; history; text; internal format)

OFFSET

0,3

LINKS

Table of n, a(n) for n=0..30.

EXAMPLE

The a(2) = 3 inequivalent matrices are:

[ 1 1 1 0 0 0 ] [ 1 1 1 0 0 0 ] [ 1 1 1 0 0 0 ]

[ 1 1 1 0 0 0 ] [ 1 1 0 1 0 0 ] [ 1 0 0 1 1 0 ]

[ 0 0 0 1 1 1 ] [ 0 0 1 0 1 1 ] [ 0 1 0 1 0 1 ]

[ 0 0 0 1 1 1 ] [ 0 0 0 1 1 1 ] [ 0 0 1 0 1 1 ]

CROSSREFS

Column k=3 of A377007.

Cf. A172556.

Sequence in context: A280756 A029855 A209397 * A110014 A026581 A151535

Adjacent sequences: A377000 A377001 A377002 * A377004 A377005 A377006

KEYWORD

nonn,more

AUTHOR

Andrew Howroyd, Oct 12 2024

STATUS

approved