A218594 Hilltop maps: number of 3Xn binary arrays indicating the locations of corresponding elements not exceeded by any horizontal or antidiagonal neighbor in a random 0..2 3Xn array

1, 49, 449, 3565, 28325, 225647, 1798967, 14344301, 114371203, 911903915, 7270785113, 57971383761, 462217176543, 3685347946655, 29383999805463, 234284375881311, 1867995138191173, 14893890483791275, 118751901014588395

Offset

1,2

Comments

Row 3 of A218592

Links

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

Formula

Empirical: a(n) = 7*a(n-1) +5*a(n-2) +17*a(n-3) +24*a(n-4) +118*a(n-5) +51*a(n-6) +119*a(n-7) +146*a(n-8) +278*a(n-9) -139*a(n-10) -27*a(n-11) +74*a(n-12) -248*a(n-13) -419*a(n-14) -247*a(n-15) -75*a(n-16) -11*a(n-17) +348*a(n-18) +172*a(n-19) +37*a(n-20) +37*a(n-21) -71*a(n-22) -71*a(n-23) -38*a(n-24) -16*a(n-25) +9*a(n-26) +21*a(n-27) +18*a(n-28) +14*a(n-29) +7*a(n-30) -a(n-31) -8*a(n-32) -2*a(n-33) +a(n-34) +a(n-35) -a(n-36) -a(n-37) for n>38

Example

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

Crossrefs

Sequence in context: A250081 A250082 A012097 * A263706 A263707 A061621

Adjacent sequences: A218591 A218592 A218593 * A218595 A218596 A218597

Keyword

nonn

Author

R. H. Hardin Nov 03 2012

Status

approved