A275353 Number of 3Xn 0..2 arrays with no element equal to any value at offset (-2,-1) (-2,1) or (-1,-2) and new values introduced in order 0..2.

5, 54, 288, 1536, 8192, 43712, 235072, 1264832, 6809856, 36666496, 197447168, 1063304448, 5726352128, 30839264512, 166086172928, 894467665408, 4817222467584, 25943536156672, 139721052861440, 752479440667648

Offset: 1

Author

R. H. Hardin, Jul 24 2016

Keywords

• nonn

Comments

Row 3 of A275352.

Examples

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

Links

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

Crossrefs

Cf. A275352.

Formula

Empirical: a(n) = 6*a(n-1) -2*a(n-2) -8*a(n-3) +20*a(n-4) -44*a(n-5) -160*a(n-6) -180*a(n-7) +152*a(n-8) -880*a(n-9) -928*a(n-10) +848*a(n-11) +816*a(n-12) +2752*a(n-13) +2880*a(n-14) +2560*a(n-15) -2048*a(n-16) -4096*a(n-18) for n>20