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A223834 Number of n X 4 0..1 arrays with rows and antidiagonals unimodal and columns nondecreasing. 1
11, 46, 118, 249, 471, 824, 1356, 2123, 3189, 4626, 6514, 8941, 12003, 15804, 20456, 26079, 32801, 40758, 50094, 60961, 73519, 87936, 104388, 123059, 144141, 167834, 194346, 223893, 256699, 292996, 333024, 377031, 425273, 478014, 535526, 598089 (list; graph; refs; listen; history; text; internal format)
OFFSET

1,1

COMMENTS

Column 4 of A223838.

LINKS

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

FORMULA

Empirical: a(n) = (1/3)*n^4 + (2/3)*n^3 + (31/6)*n^2 + (71/6)*n - 9 for n>1.

Conjectures from Colin Barker, Aug 23 2018: (Start)

G.f.: x*(11 - 9*x - 2*x^2 + 9*x^3 + x^4 - 2*x^5) / (1 - x)^5.

a(n) = 5*a(n-1) - 10*a(n-2) + 10*a(n-3) - 5*a(n-4) + a(n-5) for n>6.

(End)

EXAMPLE

Some solutions for n=3:

..0..0..0..0....0..0..0..0....0..0..0..0....0..0..0..0....0..1..1..0

..0..0..0..0....0..0..0..0....0..1..0..0....1..1..1..0....1..1..1..0

..0..1..1..0....0..1..1..1....0..1..1..0....1..1..1..0....1..1..1..0

CROSSREFS

Cf. A223838.

Sequence in context: A282095 A063158 A081587 * A143059 A224142 A155014

Adjacent sequences:  A223831 A223832 A223833 * A223835 A223836 A223837

KEYWORD

nonn

AUTHOR

R. H. Hardin, Mar 27 2013

STATUS

approved

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Last modified December 2 06:32 EST 2021. Contains 349437 sequences. (Running on oeis4.)