A224026 Number of 4Xn 0..3 arrays with rows nondecreasing and antidiagonals unimodal

256, 10000, 112436, 772683, 4002738, 16861106, 60614473, 192152734, 549805730, 1444560196, 3531148666, 8113219067, 17664791690, 36688857572, 73086084181, 140275448000, 260397984212, 469049039484, 822128311864, 1405576043323

Offset

1,1

Comments

Row 4 of A224024

Links

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

Formula

Empirical: a(n) = (3551/47900160)*n^12 + (89357/39916800)*n^11 + (787537/21772800)*n^10 + (54391/145152)*n^9 + (3628073/1451520)*n^8 + (219389/19200)*n^7 + (790310011/21772800)*n^6 + (11979533/145152)*n^5 + (26980967/217728)*n^4 + (119696723/907200)*n^3 + (46358119/831600)*n^2 + (56717/396)*n + 52 for n>2

Example

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

Crossrefs

Sequence in context: A191496 A016960 A224393 * A237966 A205936 A264496

Adjacent sequences: A224023 A224024 A224025 * A224027 A224028 A224029

Keyword

nonn

Author

R. H. Hardin Mar 30 2013

Status

approved