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A224026 Number of 4Xn 0..3 arrays with rows nondecreasing and antidiagonals unimodal 1
256, 10000, 112436, 772683, 4002738, 16861106, 60614473, 192152734, 549805730, 1444560196, 3531148666, 8113219067, 17664791690, 36688857572, 73086084181, 140275448000, 260397984212, 469049039484, 822128311864, 1405576043323 (list; graph; refs; listen; history; text; internal format)
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

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Last modified August 21 18:38 EDT 2019. Contains 326168 sequences. (Running on oeis4.)