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A224282 Number of 3Xn 0..3 arrays with diagonals and rows unimodal and antidiagonals nondecreasing 1
64, 1600, 13683, 84132, 442089, 2059793, 8626382, 32788075, 114177368, 367630559, 1103854119, 3114501259, 8312578140, 21108455323, 51251494995, 119493052710, 268514504126, 583406544627, 1229033304669, 2516545359868, 5019124209561 (list; graph; refs; listen; history; text; internal format)
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

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Last modified October 1 13:29 EDT 2022. Contains 357149 sequences. (Running on oeis4.)