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A201272 Number of n X 3 0..2 arrays with every row and column nondecreasing rightwards and downwards, and the number of instances of each value within one of each other. 2
1, 4, 7, 14, 21, 41, 54, 86, 120, 168, 218, 307, 377, 496, 621, 776, 937, 1177, 1380, 1676, 1984, 2344, 2716, 3221, 3665, 4260, 4875, 5570, 6285, 7201, 8026, 9074, 10152, 11344, 12566, 14071, 15449, 17136, 18865, 20748, 22673, 24977, 27112, 29656, 32256, 35056 (list; graph; refs; listen; history; text; internal format)
OFFSET

1,2

COMMENTS

Column 3 of A201277.

LINKS

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

FORMULA

Empirical: a(n) = 2*a(n-2) + 2*a(n-3) - a(n-4) - 4*a(n-5) + 2*a(n-7) - 2*a(n-9) + 4*a(n-11) + a(n-12) - 2*a(n-13) - 2*a(n-14) + a(n-16).

Empirical g.f.: x*(1 + 4*x + 5*x^2 + 4*x^3 + 7*x^5 + 7*x^6 + 2*x^7 - x^8 + x^9 + 4*x^10 + x^11 - 2*x^12 - 2*x^13 + x^15) / ((1 - x)^5*(1 + x)^3*(1 - x + x^2)*(1 + x + x^2)^3). - Colin Barker, Mar 02 2018

EXAMPLE

Some solutions for n=5:

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

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

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

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

..1..2..2....2..2..2....1..2..2....2..2..2....2..2..2....1..1..2....2..2..2

CROSSREFS

Cf. A201277.

Sequence in context: A171378 A147478 A147372 * A147440 A146678 A146417

Adjacent sequences:  A201269 A201270 A201271 * A201273 A201274 A201275

KEYWORD

nonn

AUTHOR

R. H. Hardin, Nov 29 2011

STATUS

approved

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Last modified July 11 22:52 EDT 2020. Contains 335652 sequences. (Running on oeis4.)