A223995 Number of nX4 0..2 arrays with antidiagonals unimodal and rows and diagonals nondecreasing

15, 155, 1144, 7927, 55333, 388598, 2743444, 19437479, 138010718, 981047716, 6977843175, 49645292212, 353262192994, 2513898151334, 17890175634324, 127318180862693, 906089796193803, 6448444001034017, 45892351529878911

Offset

1,1

Comments

Column 4 of A223999

Links

R. H. Hardin, Table of n, a(n) for n = 1..210

Formula

Empirical: a(n) = 15*a(n-1) -69*a(n-2) +66*a(n-3) +226*a(n-4) -172*a(n-5) -1192*a(n-6) +2157*a(n-7) -1714*a(n-8) -2876*a(n-9) +4966*a(n-10) +12095*a(n-11) -17584*a(n-12) +28968*a(n-13) +156*a(n-14) -2874*a(n-15) -2964*a(n-16) +15876*a(n-17) +1008*a(n-18) for n>19

Example

Some solutions for n=3
..0..0..2..2....0..1..1..1....0..0..0..0....0..0..1..1....0..1..1..2
..0..1..1..2....1..1..1..2....0..0..2..2....0..0..2..2....0..0..1..2
..1..1..1..1....0..2..2..2....1..1..1..2....0..2..2..2....0..0..1..1

Crossrefs

Sequence in context: A278803 A157380 A098685 * A323971 A006096 A346843

Adjacent sequences: A223992 A223993 A223994 * A223996 A223997 A223998

Keyword

nonn

Author

R. H. Hardin Mar 30 2013

Status

approved