A202731 Number of n X 4 nonnegative integer arrays each row and column an ascent sequence (interior element no greater than one plus up-steps preceding it) and the lower right element equal to min(n,4)-1.

1, 4, 14, 12, 462, 10296, 184848, 3010632, 46867734, 714602604, 10794487872, 162393700356, 2438841262254, 36600358759728, 549110847639168, 8237281198316304, 123562802759399382, 1853462610207713988

Offset

1,2

Comments

Column 4 of A202735.

Links

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

Formula

Empirical: a(n) = 36*a(n-1) -492*a(n-2) +3418*a(n-3) -13215*a(n-4) +28650*a(n-5) -32500*a(n-6) +15000*a(n-7) for n>10.

Example

Some solutions for n=4
..0..0..0..0....0..0..0..0....0..0..0..0....0..0..0..0....0..0..0..0
..0..0..1..1....0..0..1..1....0..1..1..1....0..0..0..1....0..1..1..1
..0..1..1..2....0..0..1..2....0..0..1..2....0..0..1..2....0..1..2..2
..0..1..2..3....0..1..2..3....0..1..2..3....0..1..2..3....0..1..2..3

Crossrefs

Cf. A202735.

Sequence in context: A018853 A218257 A193377 * A098363 A276703 A170847

Adjacent sequences: A202728 A202729 A202730 * A202732 A202733 A202734

Keyword

nonn

Author

R. H. Hardin, Dec 23 2011

Status

approved