A274748 Number of nX7 0..2 arrays with no element equal to any value at offset (-1,-2) (0,-1) or (-1,0) and new values introduced in order 0..2.

32, 448, 7858, 143634, 2661918, 49475642, 920432562, 17123659885, 318581114142, 5927090659144, 110271727008501, 2051571144042267, 38168848457457660, 710119627548581257, 13211556323824865000, 245796923794474296948

Offset: 1

Author

R. H. Hardin, Jul 04 2016

Keywords

• nonn

Comments

Column 7 of A274749.

Examples

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

Links

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

Crossrefs

Cf. A274749.

Formula

Empirical: a(n) = 21*a(n-1) -27*a(n-2) -407*a(n-3) +1614*a(n-4) -2305*a(n-5) +777*a(n-6) +1788*a(n-7) -2530*a(n-8) +1209*a(n-9) +56*a(n-10) -295*a(n-11) +115*a(n-12) -15*a(n-13) for n>15