A246899 Number of length 7+4 0..n arrays with some pair in every consecutive five terms totalling exactly n.

1546, 140893, 2390116, 25710385, 139555230, 647845357, 2132283592, 6483573889, 16272395890, 38904095581, 82432596396, 168949326193, 318823302406, 587124413485, 1018357762960, 1733359959937, 2819557291482, 4517952689629

Offset: 1

Author

R. H. Hardin, Sep 06 2014

Keywords

• nonn

Comments

Row 7 of A246892

Examples

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

Links

• R. H. Hardin, Table of n, a(n) for n = 1..59

Formula

Empirical: a(n) = 2*a(n-1) +7*a(n-2) -16*a(n-3) -20*a(n-4) +56*a(n-5) +28*a(n-6) -112*a(n-7) -14*a(n-8) +140*a(n-9) -14*a(n-10) -112*a(n-11) +28*a(n-12) +56*a(n-13) -20*a(n-14) -16*a(n-15) +7*a(n-16) +2*a(n-17) -a(n-18)