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A220029
Number of n X 5 arrays of the minimum value of corresponding elements and their horizontal or diagonal neighbors in a random, but sorted with lexicographically nondecreasing rows and nonincreasing columns, 0..1 n X 5 array.
1
5, 12, 30, 61, 111, 187, 297, 450, 656, 926, 1272, 1707, 2245, 2901, 3691, 4632, 5742, 7040, 8546, 10281, 12267, 14527, 17085, 19966, 23196, 26802, 30812, 35255, 40161, 45561, 51487, 57972, 65050, 72756, 81126, 90197, 100007, 110595, 122001, 134266
OFFSET
1,1
COMMENTS
Column 5 of A220032.
LINKS
FORMULA
Empirical: a(n) = (1/24)*n^4 + (5/12)*n^3 + (11/24)*n^2 + (61/12)*n - 4 for n>1.
Conjectures from Colin Barker, Jul 30 2018: (Start)
G.f.: x*(5 - 13*x + 20*x^2 - 19*x^3 + 11*x^4 - 3*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....1..0..0..0..0....1..0..0..0..0
..1..0..0..0..0....1..1..0..0..0....1..0..0..0..0....1..1..0..0..0
..1..1..1..0..0....1..1..1..0..0....1..1..1..0..0....1..1..0..0..0
CROSSREFS
Cf. A220032.
Sequence in context: A277088 A009412 A009428 * A192520 A094125 A015625
KEYWORD
nonn
AUTHOR
R. H. Hardin, Dec 03 2012
STATUS
approved