A206867 Number of nX4 0..1 arrays avoiding 0 0 0 horizontally and 1 0 1 vertically

13, 169, 1153, 7675, 55063, 397221, 2841311, 20294131, 145066667, 1037297447, 7416956341, 53030329081, 379156174051, 2710908891177, 19382663085405, 138583595369137, 990854370992397, 7084476762966115, 50653072024038803

Offset

1,1

Comments

Column 4 of A206871

Links

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

Formula

Empirical: a(n) = 7*a(n-1) -9*a(n-2) +59*a(n-3) +77*a(n-4) +95*a(n-5) +211*a(n-6) -354*a(n-7) -1120*a(n-8) -115*a(n-9) +1235*a(n-10) +539*a(n-11) -820*a(n-12) -522*a(n-13) -28*a(n-14) +7*a(n-15) +88*a(n-16) +54*a(n-17) +14*a(n-18) +13*a(n-19) +a(n-20) +a(n-21)

Example

Some solutions for n=4
..0..0..1..0....1..0..0..1....0..1..1..0....0..0..1..0....0..1..1..0
..1..1..0..1....1..1..0..0....1..1..0..0....0..0..1..0....0..1..1..1
..1..0..0..1....1..0..1..0....0..1..0..0....1..1..0..0....0..1..0..1
..0..0..1..1....1..0..0..1....0..1..1..0....1..1..0..0....1..0..0..1

Crossrefs

Sequence in context: A264133 A221965 A206932 * A181220 A188562 A207084

Adjacent sequences: A206864 A206865 A206866 * A206868 A206869 A206870

Keyword

nonn

Author

R. H. Hardin Feb 13 2012

Status

approved