A202910 Number of nX2 0..7 arrays with every nonzero element less than or equal to some horizontal or vertical neighbor

8, 680, 31984, 1194376, 44344428, 1707628408, 66085464308, 2542636404496, 97688506009926, 3756426746800752, 144493565678435826, 5557405757222316520, 213730533301348703138, 8219904362839412920344, 316134938792029283711026

Offset

1,1

Comments

Column 2 of A202916

Links

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

Formula

Empirical: a(n) = 36*a(n-1) -238*a(n-2) +11172*a(n-3) +34719*a(n-4) +951582*a(n-5) +3347114*a(n-6) +29399988*a(n-7) +80056473*a(n-8) +374118253*a(n-9) +709288548*a(n-10) +1969872705*a(n-11) +2317452024*a(n-12) +3743198992*a(n-13) +2076708096*a(n-14) +1625702400*a(n-15)

Example

Some solutions for n=4
..7..6....3..3....4..2....4..5....2..6....7..5....3..0....2..3....2..0....1..5
..7..5....1..3....4..1....0..6....1..6....7..4....3..0....7..3....3..1....7..5
..5..6....5..4....3..1....4..6....7..6....1..4....2..2....7..2....3..2....7..1
..1..6....5..0....4..4....4..6....7..0....1..0....3..3....3..2....0..0....2..0

Crossrefs

Sequence in context: A278857 A334088 A343191 * A332168 A168130 A270871

Adjacent sequences: A202907 A202908 A202909 * A202911 A202912 A202913

Keyword

nonn

Author

R. H. Hardin Dec 26 2011

Status

approved