A208160 Number of nX4 0..1 arrays avoiding 0 0 0 and 1 0 1 horizontally and 0 0 1 and 0 1 0 vertically.

9, 81, 281, 981, 3893, 13825, 46611, 159545, 538479, 1783379, 5887303, 19371713, 63378811, 206749703, 673357733, 2188957835, 7106004543, 23048741587, 74706706363, 242002483927, 783622093421, 2536664872659, 8209475506107

Offset

1,1

Comments

Column 4 of A208164

Links

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

Formula

Empirical: a(n) = 5*a(n-1) -7*a(n-2) +26*a(n-3) -87*a(n-4) +51*a(n-5) -163*a(n-6) +536*a(n-7) +125*a(n-8) +462*a(n-9) -1927*a(n-10) -1705*a(n-11) -1375*a(n-12) +4932*a(n-13) +5862*a(n-14) +3665*a(n-15) -7873*a(n-16) -11151*a(n-17) -6258*a(n-18) +7798*a(n-19) +11789*a(n-20) +6835*a(n-21) -4479*a(n-22) -7296*a(n-23) -4064*a(n-24) +1214*a(n-25) +2388*a(n-26) +1296*a(n-27) -138*a(n-28) -312*a(n-29) -136*a(n-30) -12*a(n-31) +8*a(n-32) -8*a(n-33)

Example

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

Crossrefs

Sequence in context: A207914 A208040 A208029 * A207956 A207238 A207496

Adjacent sequences: A208157 A208158 A208159 * A208161 A208162 A208163

Keyword

nonn

Author

R. H. Hardin, Feb 24 2012

Status

approved