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A204223 Number of (n+1)X2 0..2 arrays with the sums of 2X2 subblocks nondecreasing rightwards and downwards 5
81, 450, 2500, 11100, 49284, 192474, 751689, 2707641, 9753129, 33291180, 113635600, 373782240, 1229484096, 3940246872, 12627691129, 39725765841, 124974269289, 387960161310, 1204352604900, 3702976839180, 11385401099076 (list; graph; refs; listen; history; text; internal format)
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

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Last modified October 19 03:54 EDT 2019. Contains 328211 sequences. (Running on oeis4.)