A218366 - OEIS

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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

(list; graph; refs; listen; history; text; internal format)

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