A185605 Number of (n+1)X2 0..3 arrays with every 2X2 subblock determinant equal to some horizontal or vertical neighbor 2X2 subblock determinant

0, 580, 2366, 22236, 118616, 891506, 5489048, 38326452, 247830606, 1678338746, 11045857798, 73974786560, 490178170074, 3269292086024, 21718260697050, 144628225929208, 961688652955234, 6400460897406340, 42574178108712958

Offset

1,2

Comments

Column 1 of A185609

Links

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

Formula

Empirical: a(n)=10*a(n-1)-6*a(n-2)-197*a(n-3)+652*a(n-4)+68*a(n-5)-4460*a(n-6)+9172*a(n-7)-2564*a(n-8)-12176*a(n-9)+34398*a(n-10)-101637*a(n-11)+116495*a(n-12)+54653*a(n-13)-228940*a(n-14)+430952*a(n-15)-746674*a(n-16)+637912*a(n-17)+95538*a(n-18)-1125709*a(n-19)+2119961*a(n-20)-2867650*a(n-21)+2135142*a(n-22)+628180*a(n-23)-2741051*a(n-24)+3448532*a(n-25)-2105927*a(n-26)+61752*a(n-27)+756653*a(n-28)-607098*a(n-29)-875751*a(n-30)+882731*a(n-31)-276007*a(n-32)-379574*a(n-33)+211346*a(n-34)+16316*a(n-35)-52955*a(n-36)+8160*a(n-37)+2952*a(n-38)+864*a(n-39) for n>40

Example

Some solutions for 3X2
..3..3....2..0....3..2....2..0....3..1....3..1....2..0....0..1....1..1....3..2
..0..0....2..0....3..2....0..0....3..2....0..0....0..0....0..2....0..0....3..1
..2..0....2..0....3..2....3..2....0..1....3..0....3..1....0..1....0..0....3..0

Crossrefs

Sequence in context: A186786 A185609 A127694 * A186784 A185606 A206616

Adjacent sequences: A185602 A185603 A185604 * A185606 A185607 A185608

Keyword

nonn

Author

R. H. Hardin Jan 31 2011

Status

approved