A211910 T(n,k)=Number of lower triangular n X n arrays colored with integers 0 upwards introduced in row major order, with no element equal to any horizontal or vertical neighbor, and containing the value n(n+1)/2-k-1.

0, 0, 2, 0, 2, 10, 0, 0, 30, 34, 0, 0, 41, 418, 86, 0, 0, 42, 2385, 3006, 181, 0, 0, 42, 6927, 55822, 14201, 337, 0, 0, 0, 11296, 605769, 637721, 51157, 575, 0, 0, 0, 12732, 3997836, 18239150, 4639742, 152650, 919, 0, 0, 0, 12839, 16321156, 350026718, 281228042

Offset: 1

Author

R. H. Hardin Apr 25 2012

Keywords

• nonn
• tabl

Comments

Table starts

...0......0........0..........0............0............0.............0

...2......2........0..........0............0............0.............0

..10.....30.......41.........42...........42............0.............0

..34....418.....2385.......6927........11296........12732.........12839

..86...3006....55822.....605769......3997836.....16321156......41808669

.181..14201...637721...18239150....350026718...4630332478...42760973281

.337..51157..4639742..281228042..12075054829.379920664201.8940557439662

.575.152650.24871596.2788818593.228741733963

Examples

			Some solutions for n=4 k=4
..0........0........0........0........0........0........0........0
..1.2......1.2......1.2......1.2......1.0......1.2......1.2......1.2
..0.3.4....3.4.2....2.3.4....2.3.4....2.3.4....3.4.0....3.1.4....3.4.0
..1.0.5.3..5.6.5.0..1.5.6.4..4.5.0.4..5.4.6.0..4.2.5.3..4.5.1.6..4.3.5.4
		

Links

• R. H. Hardin, Table of n, a(n) for n = 1..85