A246886 Number of length n+4 0..2 arrays with some pair in every consecutive five terms totalling exactly 2.

231, 673, 1961, 5711, 16621, 48393, 140893, 410197, 1194243, 3476929, 10122747, 29471409, 85803183, 249807769, 727291431, 2117439451, 6164722475, 17947999987, 52253885667, 152132191293, 442918327175, 1289514355131, 3754297734035

Offset: 1

Author

R. H. Hardin, Sep 06 2014

Keywords

• nonn

Comments

Column 2 of A246892

Examples

			Some solutions for n=6
..1....1....1....2....0....0....1....2....0....0....1....2....2....1....1....0
..2....1....2....2....0....1....1....2....2....0....1....1....0....0....0....1
..2....1....1....1....0....0....2....0....1....2....2....2....1....2....1....1
..0....1....2....1....2....0....2....0....2....1....2....2....0....1....1....2
..0....2....1....2....0....2....0....1....2....1....1....1....0....2....0....0
..0....1....2....2....0....1....1....2....0....1....1....1....1....1....0....2
..1....2....0....2....2....0....0....2....2....0....2....0....1....2....2....0
..2....1....2....0....1....2....1....0....0....2....0....0....0....2....1....2
..0....0....2....1....0....0....1....2....2....1....0....1....0....1....1....0
..1....1....1....0....0....1....2....1....2....1....2....1....0....1....1....2
		

Links

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

Formula

Empirical: a(n) = 2*a(n-1) +2*a(n-2) +a(n-3) +3*a(n-4) -2*a(n-6) -2*a(n-7) -3*a(n-8) -3*a(n-9) +a(n-11) +a(n-13) +a(n-14)