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A223962 Number of 2 X n 0..3 arrays with antidiagonals unimodal and rows and diagonals nondecreasing. 1
16, 85, 295, 805, 1876, 3906, 7470, 13365, 22660, 36751, 57421, 86905, 127960, 183940, 258876, 357561, 485640, 649705, 857395, 1117501, 1440076, 1836550, 2319850, 2904525, 3606876, 4445091, 5439385, 6612145, 7988080, 9594376 (list; graph; refs; listen; history; text; internal format)
OFFSET

1,1

COMMENTS

Row 2 of A223961.

LINKS

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

FORMULA

Empirical: a(n) = (1/144)*n^6 + (7/48)*n^5 + (157/144)*n^4 + (59/16)*n^3 + (425/72)*n^2 + (25/6)*n + 1.

Conjectures from Colin Barker, Aug 24 2018: (Start)

G.f.: x*(16 - 27*x + 36*x^2 - 35*x^3 + 21*x^4 - 7*x^5 + x^6) / (1 - x)^7.

a(n) = 7*a(n-1) - 21*a(n-2) + 35*a(n-3) - 35*a(n-4) + 21*a(n-5) - 7*a(n-6) + a(n-7) for n>7.

(End)

EXAMPLE

Some solutions for n=3:

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

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

CROSSREFS

Cf. A223961.

Sequence in context: A172213 A231941 A118675 * A252834 A050256 A223835

Adjacent sequences:  A223959 A223960 A223961 * A223963 A223964 A223965

KEYWORD

nonn

AUTHOR

R. H. Hardin, Mar 29 2013

STATUS

approved

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Last modified July 24 05:48 EDT 2019. Contains 325290 sequences. (Running on oeis4.)