A242547 Number of length n+3 0..6 arrays with no four elements in a row with pattern aabb (possibly a=b) and new values 0..6 introduced in 0..6 order

13, 43, 166, 712, 3339, 16968, 92360, 532175, 3210136, 20066475, 128848615, 843831762, 5605476437, 37615886287, 254237240993, 1726996739311, 11772647808288, 80450209850112, 550717024856208, 3774443585348691

Offset

1,1

Comments

Column 6 of A242549

Links

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

Formula

Empirical: a(n) = 16*a(n-1) -95*a(n-2) +326*a(n-3) -998*a(n-4) +2268*a(n-5) -2953*a(n-6) +5002*a(n-7) -877*a(n-8) -8932*a(n-9) -5460*a(n-10) -46536*a(n-11) -36728*a(n-12) -4608*a(n-13) +43488*a(n-14) +180288*a(n-15) +260208*a(n-16) +254016*a(n-17) +207360*a(n-18) +103680*a(n-19) +20736*a(n-20)

Example

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

Crossrefs

Sequence in context: A269236 A242545 A242546 * A242548 A104115 A063650

Adjacent sequences: A242544 A242545 A242546 * A242548 A242549 A242550

Keyword

nonn

Author

R. H. Hardin, May 17 2014

Status

approved