OFFSET
1,1
COMMENTS
Table starts
......40.....112.....352....1216....4480...17152...67072..265216..1054720
.....112.....232.....568....1624....5272...18712...70168..271384..1067032
.....352.....568....1096....2536....6952...21928...76456..283816..1091752
....1216....1624....2536....4744...10696...28744...89416..309064..1141576
....4480....5272....6952...10696...19720...43912..116872..361096..1242760
...17152...18712...21928...28744...43912...80392..177928..471304..1451272
...67072...70168...76456...89416..116872..177928..324616..716296..1892872
..265216..271384..283816..309064..361096..471304..716296.1304584..2874376
.1054720.1067032.1091752.1141576.1242760.1451272.1892872.2874376..5230600
.4206592.4231192.4280488.4379464.4578952.4984072.5818888.7586824.11515912
LINKS
R. H. Hardin, Table of n, a(n) for n = 1..309
FORMULA
Empirical for diagonal and column k (the k=2..7 recurrence also works for k=1; apparently all rows and columns satisfy the same order 3 recurrence):
diagonal: a(n) = 7*a(n-1) -14*a(n-2) +8*a(n-3)
k=1: a(n) = 6*a(n-1) -8*a(n-2)
k=2..7..(?): a(n) = 7*a(n-1) -14*a(n-2) +8*a(n-3)
EXAMPLE
Some solutions for n=4 k=4
..1..3..1..3..1....1..1..1..2..2....1..3..1..3..1....0..3..0..2..3
..1..3..1..3..1....1..1..1..2..2....3..1..3..1..3....0..3..0..2..3
..1..3..1..3..1....1..1..1..2..2....1..3..1..3..1....0..3..0..2..3
..1..3..1..3..1....1..1..1..2..2....1..3..1..3..1....0..3..0..2..3
..1..3..1..3..1....2..2..2..1..1....3..1..3..1..3....0..3..0..2..3
CROSSREFS
KEYWORD
nonn,tabl
AUTHOR
R. H. Hardin, Jan 16 2014
STATUS
approved