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

Offset: 0

Author

Andrew Howroyd, Oct 12 2024

Keywords

• nonn
• more

Examples

			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.