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A224174 Number of 3Xn 0..3 arrays with rows and antidiagonals unimodal and columns nondecreasing 1
20, 400, 4739, 38561, 242114, 1253770, 5588411, 22075529, 78911656, 259222964, 791787532, 2269535600, 6149706181, 15847969147, 39036356744, 92295124070, 210220319550, 462719488690, 986952548003, 2044823738533, 4124042889158 (list; graph; refs; listen; history; text; internal format)
OFFSET

1,1

COMMENTS

Row 3 of A224173

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 + (5153/10461394944000)*n^16 + (33323/2615348736000)*n^15 + (186871/747242496000)*n^14 + (566921/149448499200)*n^13 + (390989/8211456000)*n^12 + (13776731/28740096000)*n^11 + (283859867/73156608000)*n^10 + (359930911/14631321600)*n^9 + (13824123559/114960384000)*n^8 + (6442744127/14370048000)*n^7 + (11719345643/8895744000)*n^6 + (10048449577/3736212480)*n^5 + (1016995336979/217945728000)*n^4 + (32943067909/9081072000)*n^3 + (5801778061/735134400)*n^2 - (393478/36465)*n + 10

EXAMPLE

Some solutions for n=3

..1..1..1....2..1..0....1..1..0....0..0..1....1..1..0....0..1..2....0..3..1

..2..2..1....2..1..1....1..1..0....2..3..1....1..2..0....1..2..3....2..3..1

..2..2..3....2..1..1....1..2..3....3..3..1....1..3..3....1..2..3....2..3..2

CROSSREFS

Sequence in context: A206782 A188519 A189260 * A206891 A188759 A223866

Adjacent sequences:  A224171 A224172 A224173 * A224175 A224176 A224177

KEYWORD

nonn

AUTHOR

R. H. Hardin Mar 31 2013

STATUS

approved

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Last modified November 17 08:17 EST 2018. Contains 317275 sequences. (Running on oeis4.)