A274799 Number of n X 4 0..2 arrays with no element equal to any value at offset (-1,-2) (-2,-1) (0,-1) or (-1,0) and new values introduced in order 0..2.

4, 22, 112, 596, 3104, 16328, 85504, 448656, 2352080, 12335680, 64684112, 339207984, 1778768656, 9327806784, 48914391648, 256504556080, 1345094908224, 7053603314896, 36988695973168, 193966647764784, 1017150172662336

Offset

1,1

Links

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

Formula

Empirical: a(n) = 2*a(n-1) + 15*a(n-2) + 11*a(n-3) - 2*a(n-4) - 2*a(n-5).

Empirical g.f.: 2*x*(2 + 7*x + 4*x^2 - x^3 - x^4) / (1 - 2*x - 15*x^2 - 11*x^3 + 2*x^4 + 2*x^5). - Colin Barker, Jan 31 2019

Example

Some solutions for n=4:
..0..1..0..1. .0..1..2..1. .0..1..0..2. .0..1..2..1. .0..1..0..1
..2..0..1..2. .1..0..1..0. .2..0..2..0. .1..0..1..0. .1..0..2..0
..0..2..0..1. .0..1..2..1. .0..1..0..1. .2..1..2..1. .0..1..0..2
..2..0..2..0. .2..0..1..0. .1..0..1..0. .0..2..1..2. .2..0..1..0

Crossrefs

Column 4 of A274803.

Sequence in context: A084157 A085939 A192470 * A290591 A272435 A106835

Adjacent sequences: A274796 A274797 A274798 * A274800 A274801 A274802

Keyword

nonn

Author

R. H. Hardin, Jul 07 2016

Status

approved