A275403 Number of 4_X_n 0..2 arrays with no element equal to any value at offset (-2,-1) (-2,0) or (-1,1) and new values introduced in order 0..2.

6, 31, 178, 1011, 5758, 32771, 186538, 1061795, 6043830, 34402035, 195819682, 1114623859, 6344543534, 36113737251, 205562777626, 1170082606339, 6660219918630, 37910596295955, 215790669012498, 1228300722808403

Offset

1,1

Links

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

Formula

Empirical: a(n) = 3*a(n-1) + 11*a(n-2) + 25*a(n-3) + 2*a(n-4) - 24*a(n-5) for n>6.

Empirical g.f.: x*(6 + 13*x + 19*x^2 - 14*x^3 - 20*x^4 + 8*x^5) / (1 - 3*x - 11*x^2 - 25*x^3 - 2*x^4 + 24*x^5). - Colin Barker, Feb 04 2019

Example

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

Crossrefs

Row 4 of A275401.

Sequence in context: A343350 A036729 A321799 * A338674 A199320 A097176

Adjacent sequences: A275400 A275401 A275402 * A275404 A275405 A275406

Keyword

nonn

Author

R. H. Hardin, Jul 26 2016

Status

approved