A183664 Number of (n+1) X 2 0..6 arrays with every 2 X 2 subblock summing to 12.

231, 1225, 6951, 41209, 251991, 1577065, 10049991, 64979929, 425156151, 2809324105, 18717758631, 125589227449, 847704901911, 5751142882345, 39189002324871, 268044330063769, 1839301120097271, 12656313719435785

Offset

1,1

Comments

Column 1 of A183672.

Links

R. H. Hardin, Table of n, a(n) for n = 1..200

Formula

Empirical: a(n) = 28*a(n-1) - 322*a(n-2) + 1960*a(n-3) - 6769*a(n-4) + 13132*a(n-5) - 13068*a(n-6) + 5040*a(n-7).

Empirical g.f.: x*(231 - 5243*x + 47033*x^2 - 211729*x^3 + 499000*x^4 - 574812*x^5 + 246960*x^6) / ((1 - x)*(1 - 2*x)*(1 - 3*x)*(1 - 4*x)*(1 - 5*x)*(1 - 6*x)*(1 - 7*x)). - Colin Barker, Apr 02 2018

Example

Some solutions for 3 X 2:
..4..4....5..3....1..5....3..3....4..6....6..0....4..3....4..2....2..3....3..1
..4..0....4..0....3..3....1..5....1..1....2..4....2..3....2..4....6..1....6..2
..6..2....5..3....3..3....6..0....4..6....5..1....4..3....3..3....1..4....3..1

Crossrefs

Cf. A183672.

Sequence in context: A287472 A350368 A183672 * A260302 A211717 A029569

Adjacent sequences: A183661 A183662 A183663 * A183665 A183666 A183667

Keyword

nonn

Author

R. H. Hardin, Jan 06 2011

Status

approved