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A213792 Number of n X n 0..n symmetric arrays with every row summing to floor(n^2/2). 0
1, 1, 3, 29, 3249, 4843626, 138198204339, 87098380004205128, 1525223999399549983474977 (list; graph; refs; listen; history; text; internal format)
OFFSET

0,3

LINKS

Table of n, a(n) for n=0..8.

EXAMPLE

Some solutions for n=4

..4..4..0..0....3..2..1..2....4..2..0..2....1..3..1..3....2..1..3..2

..4..4..0..0....2..1..2..3....2..0..4..2....3..4..0..1....1..4..0..3

..0..0..4..4....1..2..3..2....0..4..1..3....1..0..3..4....3..0..2..3

..0..0..4..4....2..3..2..1....2..2..3..1....3..1..4..0....2..3..3..0

CROSSREFS

Diagonal of A213800.

Sequence in context: A319637 A003190 A322451 * A133663 A270480 A229051

Adjacent sequences:  A213789 A213790 A213791 * A213793 A213794 A213795

KEYWORD

nonn,more

AUTHOR

R. H. Hardin, Jun 20 2012

EXTENSIONS

a(0)=1 prepended and a(7)-a(8) from Andrew Howroyd, Apr 07 2020

STATUS

approved

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Last modified September 19 18:36 EDT 2021. Contains 347564 sequences. (Running on oeis4.)