A265086 Number of n X 2 arrays containing 2 copies of 0..n-1 with row sums equal and column sums equal.

1, 2, 6, 24, 120, 720, 6300, 45360, 589680, 5443200, 94802400, 1032847200, 22962139200, 291502411200, 7764316560000, 113767670016000, 3504076928352000, 58171567341888000, 2032803670113216000

Offset

1,2

Comments

Column 2 of A265089.

Links

Table of n, a(n) for n=1..19.

Example

Some solutions for n=5
..0..4....1..3....2..2....4..0....0..4....2..2....1..3....1..3....3..1....3..1
..2..2....2..2....0..4....1..3....3..1....0..4....0..4....4..0....0..4....0..4
..1..3....3..1....4..0....2..2....4..0....1..3....4..0....0..4....4..0....2..2
..4..0....4..0....3..1....3..1....2..2....4..0....2..2....2..2....2..2....4..0
..3..1....0..4....1..3....0..4....1..3....3..1....3..1....3..1....1..3....1..3

Crossrefs

Cf. A265089.

Sequence in context: A350113 A129655 A114796 * A114790 A352430 A292749

Adjacent sequences: A265083 A265084 A265085 * A265087 A265088 A265089

Keyword

nonn

Author

R. H. Hardin, Dec 01 2015

Status

approved