A207071 Number of 4Xn 0..1 arrays avoiding 0 0 1 and 0 1 0 horizontally and 0 0 1 and 1 0 1 vertically

8, 64, 216, 720, 2688, 8799, 27063, 84502, 257584, 762900, 2246895, 6565968, 18955015, 54365475, 155191828, 440404000, 1244062260, 3502380028, 9826626600, 27487369521, 76702016405, 213558055578, 593398011328, 1645981275528

Offset

1,1

Comments

Row 4 of A207068

Links

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

Formula

Empirical: a(n) = 7*a(n-1) -20*a(n-2) +60*a(n-3) -200*a(n-4) +406*a(n-5) -795*a(n-6) +1948*a(n-7) -2956*a(n-8) +4315*a(n-9) -9183*a(n-10) +10237*a(n-11) -11623*a(n-12) +25456*a(n-13) -18911*a(n-14) +17833*a(n-15) -49104*a(n-16) +18984*a(n-17) -18492*a(n-18) +71354*a(n-19) -5313*a(n-20) +14092*a(n-21) -75268*a(n-22) -12707*a(n-23) -8053*a(n-24) +56095*a(n-25) +16847*a(n-26) +4140*a(n-27) -28320*a(n-28) -9288*a(n-29) -828*a(n-30) +8208*a(n-31) +2376*a(n-32) -1296*a(n-34)

Example

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

Crossrefs

Sequence in context: A340695 A086114 A209651 * A117219 A267783 A207404

Adjacent sequences: A207068 A207069 A207070 * A207072 A207073 A207074

Keyword

nonn

Author

R. H. Hardin Feb 14 2012

Status

approved