login
A246486
Number of length 7+3 0..n arrays with no pair in any consecutive four terms totalling exactly n.
1
2, 72, 6908, 87888, 1309038, 8628792, 53733080, 226048032, 881180090, 2758803240, 8099880852, 20739933552, 50471282918, 111972509208, 238609813808, 475857371712, 918806537970, 1688132007432, 3020848830380, 5201549128080
OFFSET
1,1
COMMENTS
Row 7 of A246479.
LINKS
FORMULA
Empirical: a(n) = 3*a(n-1) +5*a(n-2) -23*a(n-3) -4*a(n-4) +76*a(n-5) -28*a(n-6) -140*a(n-7) +98*a(n-8) +154*a(n-9) -154*a(n-10) -98*a(n-11) +140*a(n-12) +28*a(n-13) -76*a(n-14) +4*a(n-15) +23*a(n-16) -5*a(n-17) -3*a(n-18) +a(n-19).
EXAMPLE
Some solutions for n=4
..1....0....4....2....1....2....4....1....0....2....3....0....2....3....3....4
..0....0....3....4....1....4....1....1....2....1....3....3....3....0....2....1
..0....2....3....1....1....3....1....1....3....0....0....0....3....0....0....2
..2....1....3....1....2....3....1....2....3....0....3....2....0....0....3....4
..1....1....0....1....0....3....4....0....3....0....3....3....2....1....0....1
..1....1....0....1....0....3....4....1....4....1....3....3....0....0....2....1
..1....4....0....1....3....4....1....0....3....0....3....4....0....2....0....1
..4....4....2....1....0....2....2....2....2....1....0....4....3....0....0....2
..1....1....0....1....0....4....1....0....3....2....3....4....3....1....3....1
..2....2....1....0....3....4....0....3....0....0....0....2....3....1....3....0
CROSSREFS
Cf. A246479.
Sequence in context: A344056 A253316 A051443 * A123072 A351764 A317346
KEYWORD
nonn
AUTHOR
R. H. Hardin, Aug 27 2014
STATUS
approved