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A224144 Number of n X 6 0..1 arrays with rows and antidiagonals unimodal and columns nondecreasing. 1
22, 148, 554, 1573, 3827, 8375, 16885, 31841, 56783, 96579, 157729, 248701, 380299, 566063, 822701, 1170553, 1634087, 2242427, 3029913, 4036693, 5309347, 6901543, 8874725, 11298833, 14253055, 17826611, 22119569, 27243693, 33323323, 40496287 (list; graph; refs; listen; history; text; internal format)
OFFSET

1,1

COMMENTS

Column 6 of A224146.

LINKS

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

FORMULA

Empirical: a(n) = (2/45)*n^6 + (4/15)*n^5 + (16/9)*n^4 + 6*n^3 + (683/45)*n^2 + (341/15)*n - 55 for n>3.

Conjectures from Colin Barker, Aug 28 2018: (Start)

G.f.: x*(22 - 6*x - 20*x^2 + 33*x^3 + 40*x^4 - 53*x^5 + 8*x^6 + 11*x^7 - 2*x^8 - x^9) / (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>10.

(End)

EXAMPLE

Some solutions for n=3:

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

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

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

CROSSREFS

Cf. A224146.

Sequence in context: A262139 A159505 A223836 * A225008 A240384 A245380

Adjacent sequences:  A224141 A224142 A224143 * A224145 A224146 A224147

KEYWORD

nonn

AUTHOR

R. H. Hardin, Mar 31 2013

STATUS

approved

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Last modified August 20 06:41 EDT 2019. Contains 326139 sequences. (Running on oeis4.)