A246736 Number of length n+4 0..7 arrays with no pair in any consecutive five terms totalling exactly 7.

9368, 47432, 241544, 1231304, 6272072, 31944440, 162700376, 828690200, 4220813912, 21498069128, 109497066248, 557706305672, 2840590647176, 14468108341688, 73691067738968, 375334033262552, 1911705731599640

Offset: 1

Author

R. H. Hardin, Sep 02 2014

Keywords

• nonn

Comments

Column 7 of A246737

Examples

			Some solutions for n=2
..5....2....5....3....5....6....4....2....0....4....0....2....1....3....4....2
..0....7....0....2....7....6....1....0....5....0....4....1....0....3....6....2
..0....1....6....1....4....5....5....0....3....4....0....0....1....3....2....4
..1....1....3....7....4....6....1....2....1....6....6....0....5....0....4....6
..1....3....0....3....6....7....5....4....3....2....4....1....5....0....0....7
..3....1....3....3....7....4....0....4....5....0....2....1....3....2....0....2
		

Links

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

Formula

Empirical: a(n) = 4*a(n-1) +4*a(n-2) +4*a(n-3) +18*a(n-4) +12*a(n-5) -4*a(n-7) -a(n-8)