A184470 1/6 the number of (n+2)X4 0..2 arrays with each 3X3 subblock containing one of one value, four of another, and four of the last.

1095, 2755, 7085, 19119, 62213, 200215, 645837, 2386807, 8440325, 29121087, 112850957, 413112487, 1461095205, 5765335615, 21394180445, 76423033479, 303819408773, 1133934761455, 4067862256797, 16225029630247, 60710982378005

Offset: 1

Author

R. H. Hardin Jan 15 2011

Keywords

• nonn

Comments

Column 2 of A184477

Examples

			Some solutions with a(1,1)=0 for 6X4
..0..0..0..2....0..1..1..0....0..1..1..0....0..1..0..1....0..0..2..0
..2..2..0..0....1..1..0..0....0..1..2..0....1..0..0..1....2..0..2..1
..2..2..1..2....0..2..0..1....0..1..0..0....1..2..1..0....1..2..0..2
..0..0..0..2....1..0..1..1....0..1..1..0....0..1..0..1....0..0..2..0
..2..2..0..0....1..0..1..0....1..0..2..1....0..1..0..0....2..2..0..1
..2..1..2..2....0..2..0..1....0..1..0..0....1..2..1..0....1..2..0..2
		

Links

• R. H. Hardin, Table of n, a(n) for n = 1..200

Formula

Empirical: a(n)=5*a(n-1)-6*a(n-2)+123*a(n-3)-615*a(n-4)+738*a(n-5)-5552*a(n-6)+27760*a(n-7)-33312*a(n-8)+122328*a(n-9)-611640*a(n-10)+733968*a(n-11)-1443600*a(n-12)+7218000*a(n-13)-8661600*a(n-14)+9366192*a(n-15)-46830960*a(n-16)[phone]*a(n-17)-32980608*a(n-18)[phone]*a(n-19)-197883648*a(n-20)[phone]*a(n-21)-292066560*a(n-22)[phone]*a(n-23)-40310784*a(n-24)[phone]*a(n-25)-241864704*a(n-26)