A204223 Number of (n+1)X2 0..2 arrays with the sums of 2X2 subblocks nondecreasing rightwards and downwards

81, 450, 2500, 11100, 49284, 192474, 751689, 2707641, 9753129, 33291180, 113635600, 373782240, 1229484096, 3940246872, 12627691129, 39725765841, 124974269289, 387960161310, 1204352604900, 3702976839180, 11385401099076

Offset

1,1

Comments

Column 1 of A204230

Links

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

Formula

Empirical: a(n) = 9*a(n-1) -2*a(n-2) -210*a(n-3) +498*a(n-4) +1782*a(n-5) -7500*a(n-6) -4716*a(n-7) +53007*a(n-8) -25623*a(n-9) -209346*a(n-10) +253710*a(n-11) +460144*a(n-12) -940824*a(n-13) -427120*a(n-14) +1906032*a(n-15) -338256*a(n-16) -2148336*a(n-17) +1287648*a(n-18) +1144800*a(n-19) -1233792*a(n-20) -62208*a(n-21) +414720*a(n-22) -124416*a(n-23)

Example

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

Crossrefs

Sequence in context: A235441 A235406 A253742 * A205215 A206223 A236669

Adjacent sequences: A204220 A204221 A204222 * A204224 A204225 A204226

Keyword

nonn

Author

R. H. Hardin Jan 13 2012

Status

approved