A213796 Number of n X n 0..4 symmetric arrays with every row summing to 2*n.

1, 1, 5, 57, 3249, 815263, 932587453, 4893373431575, 119570350092328225, 13715276642286471266345, 7439775168632414842497242951, 19190656372074846793620422063221831, 236483103820478991417179706813598595965425

Offset

0,3

Links

Table of n, a(n) for n=0..12.

Example

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

Crossrefs

Column 4 of A213800.

Sequence in context: A209739 A209460 A209522 * A086060 A068003 A295902

Adjacent sequences: A213793 A213794 A213795 * A213797 A213798 A213799

Keyword

nonn

Author

R. H. Hardin, Jun 20 2012

Extensions

a(0)=1 prepended and a(8)-a(12) from Andrew Howroyd, Apr 07 2020

Status

approved