A238173 Number of (n+1) X (1+1) 0..2 arrays with the maximum plus the minimum of every 2 X 2 subblock equal.

81, 423, 2329, 13447, 79641, 479703, 2918233, 17859079, 109676409, 674920407, 4158200569, 25636328263, 158116883673, 975438912855, 6018376002073, 37135707651847, 229151775103929, 1414053340986711, 8725990453989049

Offset

1,1

Links

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

Formula

Empirical: a(n) = 10*a(n-1) - 22*a(n-2) - 20*a(n-3) + 63*a(n-4) - 6*a(n-5) - 24*a(n-6).

Empirical g.f.: x*(81 - 387*x - 119*x^2 + 1083*x^3 - 234*x^4 - 456*x^5) / ((1 - x)*(1 - 3*x - 2*x^2)*(1 - 6*x - 3*x^2 + 12*x^3)). - Colin Barker, Oct 24 2018

Example

Some solutions for n=5:
..2..0....2..0....1..0....2..2....0..1....2..2....0..1....0..0....2..0....0..1
..2..0....2..2....0..2....0..1....2..1....0..2....1..1....0..2....0..1....0..2
..2..0....0..2....0..0....0..2....2..0....1..0....0..0....1..1....2..1....2..2
..0..1....1..2....2..0....0..0....2..0....1..2....1..1....0..2....0..2....2..0
..2..0....1..0....1..1....2..2....0..2....1..0....0..1....2..1....1..2....0..2
..2..2....2..1....2..0....0..0....0..0....2..2....1..1....0..0....1..0....2..0

Crossrefs

Column 1 of A238180.

Sequence in context: A206414 A205979 A206661 * A206407 A236610 A236704

Adjacent sequences: A238170 A238171 A238172 * A238174 A238175 A238176

Keyword

nonn

Author

R. H. Hardin, Feb 19 2014

Status

approved