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A250141
Number of length 2+2 0..n arrays with the medians of every three consecutive terms nondecreasing.
1
14, 67, 204, 485, 986, 1799, 3032, 4809, 7270, 10571, 14884, 20397, 27314, 35855, 46256, 58769, 73662, 91219, 111740, 135541, 162954, 194327, 230024, 270425, 315926, 366939, 423892, 487229, 557410, 634911, 720224, 813857, 916334, 1028195
OFFSET
1,1
LINKS
FORMULA
Empirical: a(n) = (2/3)*n^4 + (10/3)*n^3 + (16/3)*n^2 + (11/3)*n + 1.
Conjectures from Colin Barker, Nov 11 2018: (Start)
G.f.: x*(14 - 3*x + 9*x^2 - 5*x^3 + x^4) / (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>5.
(End)
EXAMPLE
Some solutions for n=6:
3 6 0 3 0 4 1 4 1 4 3 6 6 4 0 2
1 4 3 3 1 0 4 5 4 6 3 0 6 1 2 6
4 4 5 4 5 3 2 4 3 2 5 5 6 4 2 2
5 0 5 5 6 3 4 5 4 5 4 5 4 5 4 3
CROSSREFS
Row 2 of A250140.
Sequence in context: A280401 A221703 A064096 * A071616 A008529 A075480
KEYWORD
nonn
AUTHOR
R. H. Hardin, Nov 13 2014
STATUS
approved