A204700 Number of nX3 0..2 arrays with no occurrence of three equal elements in a row horizontally, vertically or nw-to-se diagonally, and new values 0..2 introduced in row major order.

4, 96, 1417, 22869, 362020, 5767683, 91733605, 1459710274, 23224443905, 369522237415, 5879375305236, 93545539546075, 1488382733670257, 23681339437114202, 376788704103588493, 5995004229216188035

Offset: 1

Author

R. H. Hardin Jan 18 2012

Keywords

• nonn

Comments

Column 3 of A204705

Examples

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

Links

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

Formula

Empirical: a(n) = 9*a(n-1) +117*a(n-2) -24*a(n-3) -1482*a(n-4) +884*a(n-5) +6805*a(n-6) -7217*a(n-7) +875*a(n-8) -9444*a(n-9) +23926*a(n-10) -157560*a(n-11) +235676*a(n-12) +268960*a(n-13) -735296*a(n-14) +199456*a(n-15) +747264*a(n-16) -760384*a(n-17) -340800*a(n-18) +784192*a(n-19) -38208*a(n-20) -346880*a(n-21) +138880*a(n-22) +50176*a(n-23) -91904*a(n-24) +17408*a(n-25) +25600*a(n-26) -8192*a(n-27) -4096*a(n-28) for n>31