A207681 Number of n X 7 0..1 arrays avoiding 0 0 0 and 1 0 1 horizontally and 0 0 1 and 1 1 1 vertically.

28, 784, 1488, 4846, 14090, 29982, 65564, 139730, 299064, 620638, 1251316, 2595908, 5260942, 10606968, 21437670, 42824016, 86024822, 171420110, 340644210, 678395210, 1341990252, 2658199478, 5253155166, 10354111212, 20425614060

Offset

1,1

Comments

Column 7 of A207682.

Links

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

Formula

Empirical: a(n) = a(n-1) +4*a(n-2) +12*a(n-3) -22*a(n-4) -40*a(n-5) -69*a(n-6) +158*a(n-7) +209*a(n-8) +288*a(n-9) -681*a(n-10) -783*a(n-11) -870*a(n-12) +2056*a(n-13) +2292*a(n-14) +1834*a(n-15) -4575*a(n-16) -5470*a(n-17) -2549*a(n-18) +7882*a(n-19) +10555*a(n-20) +1934*a(n-21) -11218*a(n-22) -15926*a(n-23) +220*a(n-24) +14043*a(n-25) +18249*a(n-26) -2662*a(n-27) -15584*a(n-28) -15641*a(n-29) +4007*a(n-30) +14677*a(n-31) +9830*a(n-32) -3939*a(n-33) -11106*a(n-34) -4248*a(n-35) +2891*a(n-36) +6465*a(n-37) +985*a(n-38) -1563*a(n-39) -2801*a(n-40) +99*a(n-41) +589*a(n-42) +877*a(n-43) -170*a(n-44) -144*a(n-45) -191*a(n-46) +63*a(n-47) +20*a(n-48) +27*a(n-49) -12*a(n-50) -a(n-51) -2*a(n-52) +a(n-53) for n>60.

Example

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

Crossrefs

Cf. A207682.

Sequence in context: A209228 A208505 A207878 * A207894 A207884 A207761

Adjacent sequences: A207678 A207679 A207680 * A207682 A207683 A207684

Keyword

nonn

Author

R. H. Hardin, Feb 19 2012

Status

approved