A235946 Number of (n+1) X (n+1) 0..2 arrays colored with the upper median value of each 2 X 2 subblock.

81, 722, 1494, 2356, 5358, 10420, 21288, 49860, 114312, 228100, 449256, 1104660, 2526024, 5184100, 9904296, 25347060, 57842184, 121308100, 226373736, 597365460, 1361119944, 2899992100, 5319604776, 14353159860, 32669044104, 70376436100

Offset

1,1

Links

R. H. Hardin, Table of n, a(n) for n = 1..36

Formula

Empirical: a(n) = 41*a(n-4) -400*a(n-8) for n>13.

Empirical g.f.: x*(81 + 722*x + 1494*x^2 + 2356*x^3 + 2037*x^4 - 19182*x^5 - 39966*x^6 - 46736*x^7 - 72966*x^8 + 89680*x^9 + 174048*x^10 + 2800*x^11 - 17568*x^12) / ((1 - 2*x)*(1 + 2*x)*(1 + 4*x^2)*(1 - 5*x^2)*(1 + 5*x^2)). - Colin Barker, Oct 20 2018

Example

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

Crossrefs

Diagonal of A235954.

Sequence in context: A185366 A232026 A133549 * A090257 A295233 A271829

Adjacent sequences: A235943 A235944 A235945 * A235947 A235948 A235949

Keyword

nonn

Author

R. H. Hardin, Jan 17 2014

Status

approved