A275567 Number of 4Xn 0..2 arrays with no element equal to any value at offset (-2,0) (-1,2) or (0,-2) and new values introduced in order 0..2.

6, 216, 504, 1176, 3192, 8664, 23712, 64896, 180960, 504600, 1418100, 3985350, 11202990, 31492086, 88441764, 248378136, 697381260, 1958065350, 5498516310, 15440588646, 43363859406, 121784495766, 342029032494, 960580887846

Offset: 1

Author

R. H. Hardin, Aug 01 2016

Keywords

• nonn

Comments

Row 4 of A275565.

Examples

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

Links

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

Crossrefs

Cf. A275565.

Formula

Empirical: a(n) = 5*a(n-1) -35*a(n-3) +31*a(n-4) +131*a(n-5) -205*a(n-6) -254*a(n-7) +705*a(n-8) -6*a(n-9) -1218*a(n-10) +823*a(n-11) +1150*a(n-12) -1646*a(n-13) -439*a(n-14) +1789*a(n-15) -394*a(n-16) -1015*a(n-17) +499*a(n-18) +285*a(n-19) -205*a(n-20) -46*a(n-21) +51*a(n-22) -6*a(n-24) +a(n-25) for n>28