A246740 Number of length 3+4 0..n arrays with no pair in any consecutive five terms totalling exactly n

2, 22, 548, 2884, 18966, 66378, 241544, 643048, 1687850, 3716830, 7980972, 15368172, 28868798, 50412754, 86141456, 139758928, 222590034, 341128998, 514651700, 753789460, 1089386342, 1537935322, 2146429848, 2939373624

Offset

1,1

Comments

Row 3 of A246737

Links

R. H. Hardin, Table of n, a(n) for n = 1..71

Formula

Empirical: a(n) = 3*a(n-1) +2*a(n-2) -14*a(n-3) +5*a(n-4) +25*a(n-5) -20*a(n-6) -20*a(n-7) +25*a(n-8) +5*a(n-9) -14*a(n-10) +2*a(n-11) +3*a(n-12) -a(n-13)

Example

Some solutions for n=4
..2....4....1....3....2....0....4....3....0....4....0....4....3....3....4....4
..4....4....2....3....1....3....3....2....3....1....1....1....3....2....1....3
..4....4....1....3....1....0....3....0....2....1....0....4....3....4....4....4
..3....1....1....3....1....3....3....0....0....2....2....2....4....4....1....3
..4....2....1....2....1....3....2....3....3....4....1....1....2....4....2....3
..3....4....1....0....0....0....3....3....3....1....1....1....3....4....1....2
..4....1....2....3....1....0....3....3....3....1....1....4....4....2....4....3

Crossrefs

Sequence in context: A090313 A110129 A328020 * A248798 A120419 A217912

Adjacent sequences: A246737 A246738 A246739 * A246741 A246742 A246743

Keyword

nonn

Author

R. H. Hardin, Sep 02 2014

Status

approved