A207238 Number of nX4 0..1 arrays avoiding 0 0 0 and 0 1 1 horizontally and 0 0 1 and 0 1 0 vertically

9, 81, 283, 987, 3866, 13494, 44730, 150608, 498551, 1615388, 5213924, 16743300, 53330410, 169085209, 534330613, 1682097877, 5278749205, 16525845242, 51617974464, 160893899363, 500630178086, 1555278833939, 4824719777577

Offset

1,1

Comments

Column 4 of A207242

Links

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

Formula

Empirical: a(n) = 5*a(n-1) -6*a(n-2) +24*a(n-3) -87*a(n-4) +24*a(n-5) -155*a(n-6) +534*a(n-7) +401*a(n-8) +731*a(n-9) -1499*a(n-10) -2615*a(n-11) -3148*a(n-12) +1796*a(n-13) +6170*a(n-14) +7794*a(n-15) +630*a(n-16) -7609*a(n-17) -10518*a(n-18) -4095*a(n-19) +4874*a(n-20) +8369*a(n-21) +4506*a(n-22) -1299*a(n-23) -3802*a(n-24) -2467*a(n-25) -86*a(n-26) +905*a(n-27) +680*a(n-28) +144*a(n-29) -96*a(n-30) -82*a(n-31) -27*a(n-32) -a(n-33) +4*a(n-34) +2*a(n-35)

Example

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

Crossrefs

Sequence in context: A208029 A208160 A207956 * A207496 A208165 A207244

Adjacent sequences: A207235 A207236 A207237 * A207239 A207240 A207241

Keyword

nonn

Author

R. H. Hardin Feb 16 2012

Status

approved