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

Author

R. H. Hardin Mar 30 2013

Keywords

• nonn

Comments

Row 4 of A224024

Examples

			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
		

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