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A224136
Number of 5 X n 0..1 arrays with rows nondecreasing and antidiagonals unimodal.
1
32, 243, 748, 1635, 3149, 5648, 9577, 15505, 24141, 36350, 53169, 75823, 105741, 144572, 194201, 256765, 334669, 430602, 547553, 688827, 858061, 1059240, 1296713, 1575209, 1899853, 2276182, 2710161, 3208199, 3777165, 4424404, 5157753, 5985557
OFFSET
1,1
COMMENTS
Row 5 of A224133.
LINKS
FORMULA
Empirical: a(n) = (2/15)*n^5 + (7/6)*n^4 + (47/6)*n^3 + (173/6)*n^2 + (1981/30)*n - 27 for n>3.
Conjectures from Colin Barker, Aug 27 2018: (Start)
G.f.: x*(32 + 51*x - 230*x^2 + 152*x^3 + 179*x^4 - 228*x^5 + 18*x^6 + 63*x^7 - 21*x^8) / (1 - x)^6.
a(n) = 6*a(n-1) - 15*a(n-2) + 20*a(n-3) - 15*a(n-4) + 6*a(n-5) - a(n-6) for n>9.
(End)
EXAMPLE
Some solutions for n=3:
..0..0..1....0..0..0....1..1..1....1..1..1....0..0..1....0..0..1....0..1..1
..0..0..0....0..1..1....0..0..1....0..1..1....0..1..1....0..0..1....1..1..1
..0..0..0....0..0..1....0..1..1....0..1..1....1..1..1....0..1..1....0..1..1
..1..1..1....0..0..1....1..1..1....0..1..1....0..0..0....0..0..0....1..1..1
..0..0..1....0..0..0....0..0..1....1..1..1....0..0..1....0..0..1....0..0..0
CROSSREFS
Cf. A224133.
Sequence in context: A104782 A186774 A223952 * A250363 A346637 A017674
KEYWORD
nonn
AUTHOR
R. H. Hardin, Mar 31 2013
STATUS
approved