A250085 Number of length 4+5 0..n arrays with every six consecutive terms having the maximum of some two terms equal to the minimum of the remaining four terms.

252, 5084, 42936, 222329, 847708, 2623376, 6978064, 16547001, 35852668, 72229740, 137044040, 247259649, 427412636, 712054192, 1148730272, 1801569169, 2755552764, 4121551516, 6042207576, 8698754729, 12318868188, 17185641584

Offset

1,1

Links

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

Formula

Empirical: a(n) = (3/28)*n^8 + (121/35)*n^7 + (85/4)*n^6 + (501/10)*n^5 + (249/4)*n^4 + (1717/30)*n^3 + (1159/28)*n^2 + (1597/105)*n + 1.

Conjectures from Colin Barker, Nov 11 2018: (Start)

G.f.: x*(252 + 2816*x + 6252*x^2 - 2239*x^3 - 2861*x^4 + 56*x^5 + 52*x^6 - 9*x^7 + x^8) / (1 - x)^9.

a(n) = 9*a(n-1) - 36*a(n-2) + 84*a(n-3) - 126*a(n-4) + 126*a(n-5) - 84*a(n-6) + 36*a(n-7) - 9*a(n-8) + a(n-9) for n>9.

(End)

Example

Some solutions for n=3:
  3  2  2  0  2  2  3  3  3  2  1  0  1  0  3  1
  0  0  2  2  0  3  3  3  3  2  0  3  1  2  3  1
  2  1  1  2  0  0  3  2  1  0  0  3  3  2  2  1
  3  0  1  0  2  1  0  0  1  3  2  2  1  0  1  1
  2  0  0  0  0  1  0  0  3  2  2  0  1  0  1  3
  2  1  2  0  0  2  0  0  1  2  0  0  2  0  1  3
  2  0  1  1  0  2  2  0  1  2  1  0  1  3  3  0
  3  2  1  3  0  2  1  0  1  2  0  3  2  3  2  1
  0  1  3  1  1  0  0  3  1  2  0  3  3  0  0  3

Crossrefs

Row 4 of A250081.

Sequence in context: A169713 A099059 A151610 * A024018 A270853 A177301

Adjacent sequences: A250082 A250083 A250084 * A250086 A250087 A250088

Keyword

nonn

Author

R. H. Hardin, Nov 11 2014

Status

approved