A250066 Number of length 7+6 0..n arrays with no seven consecutive terms having the maximum of any two terms equal to the minimum of the remaining five terms.

21, 21276, 2398187, 81138873, 1329866076, 13468748489, 96884873906, 539919000270, 2469626954391, 9653001714762, 33196888242117, 102660657566831, 290292185100918, 760444039774479, 1864760913276308, 4316829401163980

Offset

1,1

Comments

Row 7 of A250059.

Links

R. H. Hardin, Table of n, a(n) for n = 1..31

Formula

Empirical: a(n) = n^13 - (3403/2772)*n^12 + (261607/27720)*n^11 - (14911/2160)*n^10 + (9505/3024)*n^9 + (10147/315)*n^8 - (59251/1260)*n^7 + (112411/5040)*n^6 + (161177/5040)*n^5 - (34699/1080)*n^4 + (17917/1512)*n^3 - (104141/27720)*n^2 + (529/4620)*n.

Empirical g.f.: x*(21 + 20982*x + 2102234*x^2 + 49492727*x^3 + 404433428*x^4 + 1382576034*x^5 + 2163711902*x^6 + 1598287676*x^7 + 544743783*x^8 + 77937032*x^9 + 3687800*x^10 + 27181*x^11) / (1 - x)^14. - Colin Barker, Sep 08 2017

Example

Some solutions for n=2
..1....2....1....2....2....1....1....2....0....2....0....0....0....2....2....2
..1....2....0....2....2....1....0....1....2....2....2....2....1....2....2....0
..2....2....0....0....2....1....2....1....1....1....2....1....2....0....2....2
..1....1....2....1....2....0....1....2....2....0....2....1....0....2....0....2
..2....2....2....2....1....0....1....1....0....0....2....2....2....2....1....2
..0....2....2....2....2....2....2....0....1....2....1....1....2....1....2....1
..0....0....1....2....0....2....0....0....1....2....0....0....2....2....2....2
..2....2....2....2....0....1....1....1....0....1....0....0....0....0....0....0
..2....2....2....2....1....2....0....1....2....1....2....2....1....1....2....2
..1....0....0....0....2....2....1....2....2....2....1....1....2....0....2....0
..1....2....2....0....2....2....2....1....2....0....1....2....0....1....0....2
..1....2....2....1....1....1....1....1....0....0....2....2....1....2....2....1
..0....1....2....1....2....2....2....0....1....2....2....2....2....1....1....2

Crossrefs

Sequence in context: A115485 A172724 A001167 * A299035 A189648 A351804

Adjacent sequences: A250063 A250064 A250065 * A250067 A250068 A250069

Keyword

nonn

Author

R. H. Hardin, Nov 11 2014

Status

approved