A213799 Number of n X n 0..7 symmetric arrays with every row summing to floor(n*7/2).
1, 8, 226, 52544, 84662388, 1012226679296, 87098380004205128
Offset: 1
Examples
Some solutions for n=4: ..4..4..5..1....7..0..0..7....2..3..7..2....1..1..5..7....5..4..4..1 ..4..6..0..4....0..3..6..5....3..4..0..7....1..2..4..7....4..0..3..7 ..5..0..2..7....0..6..6..2....7..0..5..2....5..4..5..0....4..3..2..5 ..1..4..7..2....7..5..2..0....2..7..2..3....7..7..0..0....1..7..5..1
Crossrefs
Cf. A213800.
Comments