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A229417 T(n,k)=Number of n X n 0..k zero-diagonal arrays with corresponding row and column sums equal 6
1, 1, 2, 1, 3, 10, 1, 4, 45, 152, 1, 5, 136, 4743, 7736, 1, 6, 325, 59008, 3801411, 1375952, 1, 7, 666, 426425, 345706336, 23938685973, 877901648, 1, 8, 1225, 2164680, 11782824375, 28256240134144, 1215663478473627, 2046320373120, 1, 9, 2080 (list; table; graph; refs; listen; history; text; internal format)
OFFSET

1,3

COMMENTS

Table starts

.........1................1....................1................1............1

.........2................3....................4................5............6

........10...............45..................136..............325..........666

.......152.............4743................59008...........426425......2164680

......7736..........3801411............345706336......11782824375.213067487016

...1375952......23938685973.......28256240134144.7093199984236625

.877901648.1215663478473627.33097994593655140864

LINKS

R. H. Hardin, Table of n, a(n) for n = 1..43

FORMULA

Empirical for row n:

n=1: a(n) = 1

n=2: a(n) = n + 1

n=3: a(n) = (1/2)*n^4 + 2*n^3 + (7/2)*n^2 + 3*n + 1

n=4: [polynomial of degree 9]

EXAMPLE

Some solutions for n=4 k=4

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

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

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

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

CROSSREFS

Column 1 is A007080

Row 3 is A037270(n+1)

Sequence in context: A301282 A246063 A332064 * A337890 A337888 A337887

Adjacent sequences:  A229414 A229415 A229416 * A229418 A229419 A229420

KEYWORD

nonn,tabl

AUTHOR

R. H. Hardin Sep 22 2013

STATUS

approved

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Last modified October 25 20:21 EDT 2021. Contains 348256 sequences. (Running on oeis4.)