A207369 Number of 4Xn 0..1 arrays avoiding 0 0 0 and 0 1 1 horizontally and 0 0 1 and 0 1 1 vertically

9, 81, 225, 784, 2304, 5625, 14641, 33856, 77284, 173056, 372100, 795664, 1664100, 3433609, 7017201, 14160169, 28355625, 56310016, 111007296, 217533001, 423742225, 821280964, 1584358416, 3043287556, 5823216100, 11102415424

Offset

1,1

Comments

Row 4 of A207368

Links

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

Formula

Empirical: a(n) = 4*a(n-1) -a(n-2) -8*a(n-3) -10*a(n-4) +30*a(n-5) +11*a(n-6) -15*a(n-7) -43*a(n-8) +21*a(n-9) -5*a(n-10) +26*a(n-11) +a(n-12) +27*a(n-13) -42*a(n-14) +3*a(n-15) -14*a(n-16) +15*a(n-17) -9*a(n-18) +17*a(n-19) -6*a(n-20) +2*a(n-21) -4*a(n-22) +2*a(n-23) -2*a(n-24) +a(n-25)

Example

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

Crossrefs

Sequence in context: A144938 A208114 A208119 * A208014 A208556 A063824

Adjacent sequences: A207366 A207367 A207368 * A207370 A207371 A207372

Keyword

nonn

Author

R. H. Hardin Feb 17 2012

Status

approved