A278203 Number of n X 3 0..1 arrays with every element both equal and not equal to some elements at offset (-1,-1) (-1,0) (-1,1) (0,-1) (0,1) (1,-1) (1,0) or (1,1), with upper left element zero.

0, 15, 97, 666, 4827, 34869, 251260, 1811189, 13056663, 94122538, 678506791, 4891196693, 35259493158, 254177432493, 1832305613593, 13208662283862, 95218154664535, 686405389318065, 4948135785116200, 35669952667919773

Offset

1,2

Links

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

Formula

Empirical: a(n) = 6*a(n-1) + 7*a(n-2) + 11*a(n-3) + 11*a(n-4) - 9*a(n-5) + 3*a(n-7) - 2*a(n-8) for n>9.

Empirical g.f.: x^2*(15 + 7*x - 21*x^2 - 13*x^3 + 13*x^4 - x^5 - 4*x^6 + 2*x^7) / (1 - 6*x - 7*x^2 - 11*x^3 - 11*x^4 + 9*x^5 - 3*x^7 + 2*x^8). - Colin Barker, Feb 09 2019

Example

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

Crossrefs

Column 3 of A278208.

Sequence in context: A298105 A283168 A232296 * A159528 A108681 A108254

Adjacent sequences: A278200 A278201 A278202 * A278204 A278205 A278206

Keyword

nonn

Author

R. H. Hardin, Nov 15 2016

Status

approved