A250686 Number of (n+1) X (3+1) 0..3 arrays with nondecreasing x(i,j)-x(i,j-1) in the i direction and nondecreasing absolute value of x(i,j)-x(i-1,j) in the j direction.

2541, 13906, 74631, 383440, 1848953, 8474002, 37322413, 159438246, 665575403, 2731006288, 11064772389, 44421077632, 177194842907, 703795289106, 2787900969927, 11027407758154, 43593798115489, 172349301152440

Offset

1,1

Comments

Column 3 of A250691.

Links

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

Formula

Empirical: a(n) = 27*a(n-1) -331*a(n-2) +2439*a(n-3) -12049*a(n-4) +42129*a(n-5) -107225*a(n-6) +201069*a(n-7) -277706*a(n-8) +278928*a(n-9) -197984*a(n-10) +94032*a(n-11) -26784*a(n-12) +3456*a(n-13) for n>17.

Example

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

Crossrefs

Cf. A250691.

Sequence in context: A248997 A234407 A135924 * A307473 A327771 A035876

Adjacent sequences: A250683 A250684 A250685 * A250687 A250688 A250689

Keyword

nonn

Author

R. H. Hardin, Nov 26 2014

Status

approved