A250021 Number of length 7+5 0..n arrays with no six consecutive terms having the maximum of any three terms equal to the minimum of the remaining three terms

20, 9090, 651144, 16813550, 226419876, 1956551556, 12294501768, 60858118860, 250423174860, 889518620342, 2803153559712, 7998958658106, 20995150489196, 51312795029880, 117921264043248, 256830905369688, 533584576037604

Offset

1,1

Comments

Row 7 of A250014

Links

R. H. Hardin, Table of n, a(n) for n = 1..33

Formula

Empirical: a(n) = n^12 - (68/35)*n^11 + (11737/1260)*n^10 - (90763/7560)*n^9 + (29389/1008)*n^8 - (1819/63)*n^7 + (2363/72)*n^6 - (457/280)*n^5 - (31987/1008)*n^4 + (180149/3780)*n^3 - (2139/70)*n^2 + (1427/210)*n

Example

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

Crossrefs

Sequence in context: A013725 A307914 A293286 * A203308 A109122 A135420

Adjacent sequences: A250018 A250019 A250020 * A250022 A250023 A250024

Keyword

nonn

Author

R. H. Hardin, Nov 10 2014

Status

approved