A251517 Number of (n+1) X (1+1) 0..3 arrays with every 2 X 2 subblock summing to 2 3 4 5 6 7 8 9 or 10.

246, 3798, 58618, 904734, 13963994, 215525422, 3326498602, 51342402526, 792437518266, 12230772022158, 188774232427978, 2913610912231614, 44969742102454874, 694079534186116462, 10712678731366753642

Offset

1,1

Links

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

Formula

Empirical: a(n) = 15*a(n-1) + 8*a(n-2) - 20*a(n-3).

Empirical g.f.: 2*x*(123 + 54*x - 160*x^2) / (1 - 15*x - 8*x^2 + 20*x^3). - Colin Barker, Nov 30 2018

Example

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

Crossrefs

Column 1 of A251524.

Sequence in context: A186788 A074995 A251524 * A293369 A212475 A186787

Adjacent sequences: A251514 A251515 A251516 * A251518 A251519 A251520

Keyword

nonn

Author

R. H. Hardin, Dec 03 2014

Status

approved