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A224052 Number of nX3 0..2 arrays with rows and columns unimodal and antidiagonals nondecreasing 1
22, 218, 1232, 5219, 18502, 57911, 164781, 433762, 1068664, 2485274, 5492414, 11598655, 23514508, 45950300, 86850332, 159256653, 284063565, 494009870, 839363352, 1395884951, 2275822878, 3642884361, 5732370123, 8877939920 (list; graph; refs; listen; history; text; internal format)
OFFSET

1,1

COMMENTS

Column 3 of A224057

LINKS

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

FORMULA

Empirical: a(n) = (1/19160064)*n^12 + (5/3193344)*n^11 + (1627/43545600)*n^10 + (751/1451520)*n^9 + (3247/580608)*n^8 + (18607/483840)*n^7 + (11286841/43545600)*n^6 + (1893037/1451520)*n^5 + (2032151/435456)*n^4 + (1618571/362880)*n^3 + (7125527/831600)*n^2 + (241067/27720)*n - 9 for n>1

EXAMPLE

Some solutions for n=3

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

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

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

CROSSREFS

Sequence in context: A232019 A224330 A223928 * A224305 A224369 A331882

Adjacent sequences:  A224049 A224050 A224051 * A224053 A224054 A224055

KEYWORD

nonn

AUTHOR

R. H. Hardin Mar 30 2013

STATUS

approved

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Last modified September 22 16:50 EDT 2020. Contains 337291 sequences. (Running on oeis4.)