A219144 Unchanging value maps: number of 3Xn binary arrays indicating the locations of corresponding elements unequal to no horizontal, diagonal or antidiagonal neighbor in a random 0..2 3Xn array.

1, 18, 78, 281, 1072, 4033, 15255, 57963, 220068, 835820, 3172817, 12044346, 45722019, 173574485, 658947323, 2501581220, 9496787730, 36052730049, 136867284190, 519590670019, 1972527813429, 7488329193659, 28428025632710

Offset: 1

Author

R. H. Hardin Nov 12 2012

Keywords

• nonn

Comments

Row 3 of A219142

Examples

			Some solutions for n=3
..1..0..1....1..0..1....0..0..1....0..0..1....1..0..0....0..0..0....0..0..0
..0..0..1....0..0..1....0..0..1....1..0..1....1..0..0....1..0..1....0..0..1
..1..0..1....0..0..1....0..0..1....1..0..0....0..0..1....0..0..1....1..0..1
		

Links

• R. H. Hardin, Table of n, a(n) for n = 1..40

Formula

Empirical: a(n) = 4*a(n-1) -8*a(n-3) +17*a(n-4) +17*a(n-5) -29*a(n-6) -13*a(n-7) +9*a(n-8) -31*a(n-9) -26*a(n-10) +30*a(n-11) -3*a(n-12) +6*a(n-13) +17*a(n-14) -3*a(n-15) +3*a(n-16) -2*a(n-17) for n>18