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A224142 Number of n X 4 0..1 arrays with rows and antidiagonals unimodal and columns nondecreasing. 1
11, 46, 124, 272, 526, 930, 1536, 2404, 3602, 5206, 7300, 9976, 13334, 17482, 22536, 28620, 35866, 44414, 54412, 66016, 79390, 94706, 112144, 131892, 154146, 179110, 206996, 238024, 272422, 310426, 352280, 398236, 448554, 503502, 563356, 628400 (list; graph; refs; listen; history; text; internal format)
OFFSET

1,1

COMMENTS

Column 4 of A224146.

LINKS

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

FORMULA

Empirical: a(n) = (1/3)*n^4 + (4/3)*n^3 + (14/3)*n^2 + (23/3)*n - 4 for n>1.

Conjectures from Colin Barker, Aug 27 2018: (Start)

G.f.: x*(11 - 9*x + 4*x^2 + 2*x^3 + x^4 - 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..1..0..0....0..0..0..0....0..0..0..0....0..0..1..0....1..1..1..0

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

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

CROSSREFS

Cf. A224146.

Sequence in context: A081587 A223834 A143059 * A155014 A006324 A256582

Adjacent sequences:  A224139 A224140 A224141 * A224143 A224144 A224145

KEYWORD

nonn

AUTHOR

R. H. Hardin, Mar 31 2013

STATUS

approved

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Last modified August 19 18:51 EDT 2019. Contains 326133 sequences. (Running on oeis4.)