A184450 1/36 the number of (n+2)X4 0..2 arrays with each 3X3 subblock containing two of one value, two of another, and five of the last

234, 600, 1591, 4517, 16029, 58413, 216477, 930657, 3947025, 16260821, 75637161, 341430753, 1469964069, 7087591425, 32968435401, 145042964117, 711996798489, 3363303213633, 14962011182037, 74119134136017, 352902194702745

Offset

1,1

Comments

Column 2 of A184457

Links

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

Formula

Empirical: a(n)=6*a(n-1)-11*a(n-2)+195*a(n-3)-1134*a(n-4)+2079*a(n-5)-11600*a(n-6)+62796*a(n-7)-115126*a(n-8)+263520*a(n-9)-1204344*a(n-10)+2207964*a(n-11)-2907648*a(n-12)+10219824*a(n-13)-18736344*a(n-14)+17243280*a(n-15)-42140736*a(n-16)+77258016*a(n-17)-55857600*a(n-18)+82301184*a(n-19)-150885504*a(n-20)+92378880*a(n-21)-60466176*a(n-22)+110854656*a(n-23)-60466176*a(n-24)

Example

Some solutions with a(1,1)=0 for 6X4
..0..0..0..0....0..0..1..2....0..1..0..0....0..0..0..0....0..0..0..0
..0..2..1..0....2..2..1..0....0..2..1..0....2..1..0..2....1..2..0..1
..1..0..2..1....2..2..2..2....0..0..2..0....2..0..1..2....0..2..1..0
..0..0..0..0....0..1..0..2....0..1..0..0....0..0..0..0....2..2..2..2
..0..2..1..0....2..1..2..0....0..1..2..0....0..1..2..0....1..2..0..1
..0..1..2..0....1..1..1..1....2..0..0..2....1..2..0..1....2..1..0..2

Crossrefs

Sequence in context: A375344 A256086 A186897 * A338391 A304615 A287878

Adjacent sequences: A184447 A184448 A184449 * A184451 A184452 A184453

Keyword

nonn

Author

R. H. Hardin Jan 14 2011

Status

approved