A213805 Number of 7 X 7 0..n symmetric arrays with all rows summing to floor(n*7/2).

1, 35150, 133721189, 46259653191, 4893373431575, 212962858290086, 5406415387421647, 87098380004205128, 1034209337638242207, 9323807379913081007, 69112259378483785503, 425995640129266136995, 2291562702094516094937, 10801522912361264775797, 46064488469672007773725

Offset

0,2

Links

Table of n, a(n) for n=0..14.

Example

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

Crossrefs

Row 7 of A213800.

Sequence in context: A251063 A234988 A075831 * A204491 A085545 A031855

Adjacent sequences: A213802 A213803 A213804 * A213806 A213807 A213808

Keyword

nonn

Author

R. H. Hardin, Jun 20 2012

Extensions

a(0)=1 prepended and terms a(6) and beyond from Andrew Howroyd, Apr 07 2020

Status

approved