A204973 Number of nX3 0..2 arrays with no occurrence of three equal elements in a row horizontally, vertically, diagonally or antidiagonally, and new values 0..2 introduced in row major order.

4, 96, 1217, 16813, 226908, 3074889, 41618941, 563504926, 7628868673, 103284942785, 1398329242622, 18931424557397, 256304779809413, 3470006246394670, 46978999502038957, 636029536681800861

Offset: 1

Author

R. H. Hardin Jan 21 2012

Keywords

• nonn

Comments

Column 3 of A204978

Examples

			Some solutions for n=5
..0..1..2....0..0..1....0..1..0....0..0..1....0..1..1....0..0..1....0..0..1
..0..2..1....0..1..1....2..1..2....2..0..0....0..1..2....0..0..1....1..2..2
..1..2..0....2..2..0....2..2..1....2..1..2....2..2..0....1..1..2....2..1..2
..1..0..0....0..1..2....0..1..1....1..1..2....0..1..1....2..1..1....2..2..0
..2..2..1....0..1..1....0..0..2....1..2..0....0..2..1....0..0..2....0..1..1
		

Links

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

Formula

Empirical: a(n) = 9*a(n-1) +79*a(n-2) -165*a(n-3) -1117*a(n-4) +1506*a(n-5) +4665*a(n-6) -8530*a(n-7) +2842*a(n-8) +16415*a(n-9) -52874*a(n-10) -90975*a(n-11) +139014*a(n-12) -2762*a(n-13) -188806*a(n-14) +657130*a(n-15) -216610*a(n-16) -282088*a(n-17) +299084*a(n-18) -320888*a(n-19) -25488*a(n-20) +130096*a(n-21) -166448*a(n-22) -3680*a(n-23) +14752*a(n-24) -23360*a(n-25) +12288*a(n-26) +6144*a(n-27)