A207415 Number of n X 4 0..1 arrays avoiding 0 0 1 and 0 1 0 horizontally and 0 1 1 and 1 0 1 vertically.

9, 81, 241, 742, 2760, 8465, 24317, 73405, 214117, 601411, 1698702, 4766632, 13156641, 36175599, 99198867, 270109351, 732494449, 1982055330, 5345239912, 14374634237, 38587852393, 103391960861, 276535572481, 738655032563

Offset

1,1

Comments

Column 4 of A207419.

Links

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

Formula

Empirical: a(n) = 5*a(n-1) -8*a(n-2) +23*a(n-3) -74*a(n-4) +70*a(n-5) -116*a(n-6) +362*a(n-7) -122*a(n-8) +152*a(n-9) -916*a(n-10) -166*a(n-11) +26*a(n-12) +1638*a(n-13) +657*a(n-14) -225*a(n-15) -1890*a(n-16) -895*a(n-17) +372*a(n-18) +1268*a(n-19) +486*a(n-20) -190*a(n-21) -454*a(n-22) -122*a(n-23) +60*a(n-24) +60*a(n-25).

Example

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

Crossrefs

Cf. A207419.

Sequence in context: A063824 A357450 A207560 * A207020 A207364 A207786

Adjacent sequences: A207412 A207413 A207414 * A207416 A207417 A207418

Keyword

nonn

Author

R. H. Hardin Feb 17 2012

Status

approved