A218282 Hilltop maps: number of nX2 binary arrays indicating the locations of corresponding elements not exceeded by any horizontal or vertical neighbor in a random 0..4 nX2 array

3, 15, 63, 255, 1019, 4073, 16289, 65153, 260609, 1042417, 4169595, 16678079, 66711107, 266839591, 1067339019, 4269278705, 17076805345, 68305983505, 273218982601, 1092856125089, 4371345280527, 17485064248535, 69938989522819

Offset

1,1

Comments

Column 2 of A218288

Links

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

Formula

Empirical: a(n) = 3*a(n-1) +3*a(n-2) +3*a(n-3) +3*a(n-4) +3*a(n-5) +3*a(n-6) +3*a(n-7) +2*a(n-8) +2*a(n-9) -a(n-10) -a(n-11) -a(n-12) -a(n-13) -a(n-14) -a(n-15) -a(n-16) -a(n-17)

Example

Some solutions for n=3
..0..1....0..1....1..1....1..1....1..0....0..0....0..0....1..1....1..1....0..0
..0..0....1..1....0..0....0..0....0..0....1..0....1..0....1..1....0..1....0..0
..0..0....0..1....0..1....1..1....1..0....0..0....1..1....1..0....1..1....1..1

Crossrefs

Sequence in context: A359082 A359083 A218236 * A103454 A024036 A111303

Adjacent sequences: A218279 A218280 A218281 * A218283 A218284 A218285

Keyword

nonn

Author

R. H. Hardin Oct 25 2012

Status

approved