A229870 - OEIS

%I #5 Dec 18 2015 18:18:42

%S 2,3,8,4,27,80,5,64,1215,2432,6,125,8704,384183,247552,7,216,40625,

%T 15106048,923742873,88060928,8,343,143856,266515625,354003288064,

%U 17451302074317,112371410944,9,512,420175,2805425280,36821326171875

%N T(n,k)=Number of n X n 0..k arrays with corresponding row and column sums equal

%C Table starts

%C ......2.........3............4..............5................6...........7

%C ......8........27...........64............125..............216.........343

%C .....80......1215.........8704..........40625...........143856......420175

%C ...2432....384183.....15106048......266515625.......2805425280.20610104767

%C .247552.923742873.354003288064.36821326171875.1656812779036416

%H R. H. Hardin, <a href="/A229870/b229870.txt">Table of n, a(n) for n = 1..43</a>

%F Empirical for row n:

%F n=1: a(n) = n + 1

%F n=2: a(n) = n^3 + 3*n^2 + 3*n + 1

%F n=3: [polynomial of degree 7]

%F n=4: [polynomial of degree 13]

%e Some solutions for n=4 k=4

%e ..0..0..0..1....0..0..0..1....0..0..0..0....0..0..1..1....0..0..1..1

%e ..0..1..2..1....0..0..3..4....0..0..3..3....0..1..0..3....0..0..2..2

%e ..1..0..0..3....1..4..2..0....0..4..0..2....1..3..4..0....1..3..4..1

%e ..0..3..2..1....0..3..2..2....0..2..3..2....1..0..3..2....1..1..2..0

%Y Row 2 is A000578(n+1)

%Y Row 3 is A168364(n+1)

%K nonn,tabl

%O 1,1

%A _R. H. Hardin_, Oct 01 2013