A224282 Number of 3Xn 0..3 arrays with diagonals and rows unimodal and antidiagonals nondecreasing

64, 1600, 13683, 84132, 442089, 2059793, 8626382, 32788075, 114177368, 367630559, 1103854119, 3114501259, 8312578140, 21108455323, 51251494995, 119493052710, 268514504126, 583406544627, 1229033304669, 2516545359868, 5019124209561

Offset

1,1

Comments

Row 3 of A224281

Links

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

Formula

Empirical: a(n) = (1/3629463552000)*n^18 + (1/80654745600)*n^17 + (1123/2092278988800)*n^16 + (37607/2615348736000)*n^15 + (1660537/5230697472000)*n^14 + (58097/11496038400)*n^13 + (870097/11496038400)*n^12 + (18766109/28740096000)*n^11 + (404719067/73156608000)*n^10 + (535345591/14631321600)*n^9 + (24473380931/160944537600)*n^8 + (549661909/449064000)*n^7 + (1232106541/768768000)*n^6 + (74468938879/3736212480)*n^5 + (59979142753/8717829120)*n^4 + (521837272841/9081072000)*n^3 + (1774626948209/5145940800)*n^2 - (140683661/117810)*n + 1114 for n>3

Example

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

Crossrefs

Sequence in context: A145218 A282526 A014794 * A224205 A162994 A225981

Adjacent sequences: A224279 A224280 A224281 * A224283 A224284 A224285

Keyword

nonn

Author

R. H. Hardin Apr 02 2013

Status

approved