A206781 Number of nX4 0..1 arrays avoiding 0 0 1 horizontally and 0 1 1 vertically

12, 144, 1020, 6752, 39276, 219061, 1165366, 6052170, 30750128, 154046108, 762592234, 3742458919, 18234837346, 88348314182, 426051182458, 2046737779538, 9800851550334, 46804771654291, 223004711416620, 1060425465768772

Offset

1,1

Comments

Column 4 of A206785

Links

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

Formula

Empirical: a(n) = 12*a(n-1) -28*a(n-2) -167*a(n-3) +737*a(n-4) +570*a(n-5) -5810*a(n-6) +1525*a(n-7) +22058*a(n-8) -14330*a(n-9) -47100*a(n-10) +38200*a(n-11) +61863*a(n-12) -52870*a(n-13) -52680*a(n-14) +42745*a(n-15) +29773*a(n-16) -20710*a(n-17) -11060*a(n-18) +5845*a(n-19) +2554*a(n-20) -872*a(n-21) -322*a(n-22) +52*a(n-23) +16*a(n-24)

Example

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

Crossrefs

Sequence in context: A206996 A188518 A207001 * A188769 A206885 A206890

Adjacent sequences: A206778 A206779 A206780 * A206782 A206783 A206784

Keyword

nonn

Author

R. H. Hardin Feb 12 2012

Status

approved