

A249961


Number of length 1+5 0..n arrays with no six consecutive terms having the maximum of any two terms equal to the minimum of the remaining four terms.


1



15, 285, 2010, 8790, 28785, 77595, 181860, 383580, 745155, 1355145, 2334750, 3845010, 6094725, 9349095, 13939080, 20271480, 28839735, 40235445, 55160610, 74440590, 99037785, 130066035, 168805740, 216719700, 275469675, 346933665
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OFFSET

1,1


COMMENTS

Row 1 of A249960.


LINKS

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


FORMULA

Empirical: a(n) = n^6 + 3*n^5 + 5*n^4 + 5*n^3 + (3/2)*n^2  (1/2)*n.
Conjectures from Colin Barker, Aug 21 2017: (Start)
G.f.: 15*x*(1 + x)^2*(1 + 10*x + x^2) / (1  x)^7.
a(n) = 7*a(n1)  21*a(n2) + 35*a(n3)  35*a(n4) + 21*a(n5)  7*a(n6) + a(n7) for n>7.
(End)


EXAMPLE

Some solutions for n=6:
..1....0....3....4....2....2....3....4....3....1....0....4....4....1....0....0
..3....4....1....2....4....5....1....2....3....3....1....2....1....6....0....3
..3....5....3....5....3....5....3....0....6....5....0....4....6....4....3....4
..5....3....1....3....0....6....2....3....6....2....2....1....5....1....6....1
..0....2....3....5....4....5....3....1....0....5....4....1....1....3....1....6
..4....0....2....1....4....3....3....6....1....0....3....2....2....5....3....4


CROSSREFS

Sequence in context: A095654 A279167 A249960 * A177074 A069405 A125055
Adjacent sequences: A249958 A249959 A249960 * A249962 A249963 A249964


KEYWORD

nonn


AUTHOR

R. H. Hardin, Nov 09 2014


STATUS

approved



