A246891 Number of length n+4 0..7 arrays with some pair in every consecutive five terms totalling exactly 7

23400, 159688, 1079680, 7216512, 47799488, 319477960, 2132283592, 14219886016, 94826520320, 632600369216, 4219646774184, 28145459043464, 187735748042496, 1252250358585088, 8352796888611456, 55715038868965512, 371632331032444552

Offset

1,1

Comments

Column 7 of A246892

Links

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

Formula

Empirical: a(n) = 4*a(n-1) +10*a(n-2) +38*a(n-3) +132*a(n-4) -233*a(n-5) -124*a(n-6) -48*a(n-7) -152*a(n-8) +232*a(n-9) +97*a(n-10) -80*a(n-11) +14*a(n-12) -6*a(n-13) -4*a(n-14) +a(n-15)

Example

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

Crossrefs

Sequence in context: A184229 A153771 A252944 * A189656 A204074 A031847

Adjacent sequences: A246888 A246889 A246890 * A246892 A246893 A246894

Keyword

nonn

Author

R. H. Hardin, Sep 06 2014

Status

approved