A218229 Hilltop maps: number of nX4 binary arrays indicating the locations of corresponding elements not exceeded by any horizontal, vertical or antidiagonal neighbor in a random 0..2 nX4 array

13, 241, 3969, 63309, 1012165, 16187585, 258892017, 4140512637, 66219989569, 1059068692053, 16937884056129, 270890753853217, 4332406590925081, 69288990493328445, 1108151809585322513, 17722879556252110069

Offset

1,1

Comments

Column 4 of A218233

Links

R. H. Hardin, Table of n, a(n) for n = 1..142

Formula

Empirical: a(n) = 13*a(n-1) +40*a(n-2) +108*a(n-3) +240*a(n-4) +682*a(n-5) +752*a(n-6) +1174*a(n-7) +1536*a(n-8) +2226*a(n-9) -1135*a(n-10) +2385*a(n-11) +2447*a(n-12) -419*a(n-13) -3212*a(n-14) +1404*a(n-15) +582*a(n-16) -932*a(n-17) -1955*a(n-18) +963*a(n-19) -38*a(n-20) -278*a(n-21) -239*a(n-22) +715*a(n-23) +4*a(n-24) -34*a(n-25) -180*a(n-26) +128*a(n-27) -81*a(n-28) -35*a(n-29) -21*a(n-30) +83*a(n-31) -10*a(n-32) +6*a(n-34) +8*a(n-35) -14*a(n-36) -a(n-40) +a(n-41)

Example

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

Crossrefs

Sequence in context: A228795 A271782 A157969 * A020520 A259420 A203156

Adjacent sequences: A218226 A218227 A218228 * A218230 A218231 A218232

Keyword

nonn

Author

R. H. Hardin Oct 24 2012

Status

approved