A281060 Number of 5Xn 0..1 arrays with no element equal to more than one of its horizontal and antidiagonal neighbors, with the exception of exactly two elements, and with new values introduced in order 0 sequentially upwards.

0, 122, 1492, 3416, 7803, 16875, 32370, 59669, 107693, 191953, 339219, 595824, 1041681, 1814253, 3149435, 5451162, 9409735, 16202663, 27835100, 47716151, 81633286, 139397983, 237621979, 404396106, 687167939, 1165993033, 1975805797

Offset

1,2

Comments

Row 5 of A281056.

Links

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

Formula

Empirical: a(n) = 6*a(n-1) -12*a(n-2) +5*a(n-3) +12*a(n-4) -12*a(n-5) -3*a(n-6) +6*a(n-7) -a(n-9) for n>18

Example

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

Crossrefs

Cf. A281056.

Sequence in context: A238033 A275181 A275129 * A274726 A249532 A222991

Adjacent sequences: A281057 A281058 A281059 * A281061 A281062 A281063

Keyword

nonn

Author

R. H. Hardin, Jan 13 2017

Status

approved