A207510 Number of nX4 0..1 arrays avoiding 0 0 0 and 0 1 1 horizontally and 0 0 1 and 1 1 1 vertically

9, 81, 166, 438, 1042, 1992, 4168, 8174, 15881, 30801, 58335, 111083, 209072, 391336, 731541, 1358864, 2519079, 4655423, 8579122, 15779179, 28954160, 53037211, 96982948, 177063128, 322816525, 587759306, 1068885187, 1941639552, 3523372673

Offset

1,1

Comments

Column 4 of A207514

Links

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

Formula

Empirical: a(n) = -a(n-1) +4*a(n-2) +14*a(n-3) +5*a(n-4) -31*a(n-5) -67*a(n-6) -28*a(n-7) +76*a(n-8) +171*a(n-9) +113*a(n-10) -61*a(n-11) -229*a(n-12) -197*a(n-13) -27*a(n-14) +154*a(n-15) +175*a(n-16) +71*a(n-17) -46*a(n-18) -89*a(n-19) -45*a(n-20) -6*a(n-21) +32*a(n-22) +12*a(n-23) +10*a(n-24) -7*a(n-25) -a(n-26) -2*a(n-27) +a(n-28) for n>32

Example

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

Crossrefs

Sequence in context: A207875 A207678 A207684 * A208104 A207725 A044260

Adjacent sequences: A207507 A207508 A207509 * A207511 A207512 A207513

Keyword

nonn

Author

R. H. Hardin Feb 18 2012

Status

approved