A206879 Number of n X 4 0..1 arrays avoiding 0 1 0 horizontally and 1 0 1 vertically.

12, 144, 1011, 6478, 44879, 321393, 2276625, 15986104, 112334542, 790951091, 5570201912, 39212133425, 276007394747, 1942896002325, 13677110916246, 96279937841588, 677755568854937, 4771010567436598, 33585249323714265

Offset

1,1

Comments

Column 4 of A206883.

Links

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

Formula

Empirical: a(n) = 8*a(n-1) -18*a(n-2) +69*a(n-3) +92*a(n-4) -189*a(n-5) +404*a(n-6) -187*a(n-7) -4014*a(n-8) -682*a(n-9) +9084*a(n-10) +5101*a(n-11) -6052*a(n-12) -5594*a(n-13) -1393*a(n-14) -277*a(n-15) +1312*a(n-16) +1153*a(n-17) +533*a(n-18) +112*a(n-19) -87*a(n-20) -46*a(n-21) -32*a(n-22) -9*a(n-23) +3*a(n-24) +a(n-25).

Example

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

Crossrefs

Cf. A206883.

Sequence in context: A190074 A188853 A188503 * A206996 A188518 A207001

Adjacent sequences: A206876 A206877 A206878 * A206880 A206881 A206882

Keyword

nonn

Author

R. H. Hardin, Feb 13 2012

Status

approved