A246001 - OEIS

A246001

Number of length 6+2 0..n arrays with no pair in any consecutive three terms totalling exactly n.

2, 56, 2308, 23168, 171942, 795144, 3057032, 9401216, 25819210, 62402840, 139927692, 288998016, 566057198, 1047126248, 1862251792, 3175741184, 5253738642, 8416795896, 13163097620, 20070807680, 30009814582, 43960191176

(list; graph; refs; listen; history; text; internal format)

OFFSET

1,1

COMMENTS

Row 6 of A245995.

LINKS

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

FORMULA

Empirical: a(n) = 3*a(n-1) +3*a(n-2) -17*a(n-3) +3*a(n-4) +39*a(n-5) -25*a(n-6) -45*a(n-7) +45*a(n-8) +25*a(n-9) -39*a(n-10) -3*a(n-11) +17*a(n-12) -3*a(n-13) -3*a(n-14) +a(n-15).

EXAMPLE

Some solutions for n=5

..0....4....3....3....0....1....0....0....4....1....4....3....0....0....4....1

..3....4....3....0....4....0....4....1....3....1....4....3....3....3....0....1

..3....5....0....0....3....0....4....3....5....0....2....1....1....4....0....1

..4....5....3....2....0....3....0....1....5....0....2....3....1....3....0....0

..4....1....1....0....4....4....3....3....4....3....0....3....2....3....1....0

..3....1....0....1....4....0....1....1....3....3....2....5....0....5....0....4

..5....1....0....1....0....2....3....1....3....3....2....5....1....1....0....3

..5....2....3....0....2....0....0....3....1....0....0....3....3....5....4....0

CROSSREFS

Cf. A245995.