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A219628
Number of 2 X n arrays of the minimum value of corresponding elements and their horizontal or antidiagonal neighbors in a random, but sorted with lexicographically nondecreasing rows and columns, 0..2 2 X n array.
1
6, 11, 24, 54, 103, 178, 290, 453, 684, 1003, 1433, 2000, 2733, 3664, 4828, 6263, 8010, 10113, 12619, 15578, 19043, 23070, 27718, 33049, 39128, 46023, 53805, 62548, 72329, 83228, 95328, 108715, 123478, 139709, 157503, 176958, 198175, 221258, 246314
OFFSET
1,1
COMMENTS
Row 2 of A219627.
LINKS
FORMULA
Empirical: a(n) = (1/8)*n^4 - (11/12)*n^3 + (63/8)*n^2 - (145/12)*n + 3 for n>3.
Conjectures from Colin Barker, Jul 26 2018: (Start)
G.f.: x*(6 - 19*x + 29*x^2 - 16*x^3 - 7*x^4 + 12*x^5 - x^6 - x^7) / (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>8.
(End)
EXAMPLE
Some solutions for n=3:
..0..0..0....0..0..2....1..1..2....0..0..1....0..0..1....0..0..1....0..0..1
..0..2..2....0..0..2....2..2..2....0..0..1....0..0..0....1..1..1....0..0..2
CROSSREFS
Cf. A219627.
Sequence in context: A063629 A076496 A354594 * A093027 A109296 A158949
KEYWORD
nonn
AUTHOR
R. H. Hardin, Nov 24 2012
STATUS
approved