A218366 Hilltop maps: number of nX2 binary arrays indicating the locations of corresponding elements not exceeded by any horizontal, vertical or antidiagonal neighbor in a random 0..3 nX2 array

3, 15, 63, 253, 1009, 4033, 16129, 64511, 258015, 1031935, 4127233, 16506913, 66019585, 264046081, 1056055299, 4223705151, 16892756671, 67562771965, 270218073025, 1080740248897, 4322432887297, 17287619374079, 69142029827999

Offset

1,1

Comments

Column 2 of A218372

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) +a(n-7) +a(n-8) +a(n-9) +a(n-10) +a(n-11) +a(n-12) +a(n-13)

Example

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

Crossrefs

Sequence in context: A218313 A218190 A216757 * A359082 A359083 A218236

Adjacent sequences: A218363 A218364 A218365 * A218367 A218368 A218369

Keyword

nonn

Author

R. H. Hardin Oct 27 2012

Status

approved