A236664 Number of (n+1) X (1+1) 0..2 arrays colored with the maximum plus the lower median minus the upper median minus the minimum of every 2 X 2 subblock.

81, 452, 2608, 14760, 84948, 484400, 2771648, 15802528, 90361616, 516384576, 2952092672, 16860669056, 96327668544, 550413844224, 3145705321472, 17974353615360, 102695841511680, 586762124067840, 3352875664056320

Offset

1,1

Links

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

Formula

Empirical: a(n) = 2*a(n-1) + 436*a(n-4) + 888*a(n-5) + 2304*a(n-6) + 5760*a(n-7).

Empirical g.f.: x*(81 + 290*x + 1704*x^2 + 9544*x^3 + 20112*x^4 + 45504*x^5 + 77760*x^6) / (1 - 2*x - 436*x^4 - 888*x^5 - 2304*x^6 - 5760*x^7). - Colin Barker, Oct 21 2018

Example

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

Crossrefs

Column 1 of A236669.

Sequence in context: A206223 A236669 A205208 * A253533 A183971 A253526

Adjacent sequences: A236661 A236662 A236663 * A236665 A236666 A236667

Keyword

nonn

Author

R. H. Hardin, Jan 29 2014

Status

approved