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A203721 Number of (n+1) X 2 0..2 arrays with column and row pair sums b(i,j)=a(i,j)+a(i,j-1) and c(i,j)=a(i,j)+a(i-1,j) nondecreasing in column and row directions, respectively. 1
32, 113, 326, 888, 2278, 5653, 13665, 32440, 75965, 176104, 405154, 926794, 2110867, 4791921, 10851104, 24525361, 55351946, 124789380, 281102434, 632821501, 1423947009, 3202968748, 7202709761, 16193929296, 36403520114, 81824939598 (list; graph; refs; listen; history; text; internal format)
OFFSET

1,1

COMMENTS

Column 1 of A203728.

LINKS

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

FORMULA

Empirical: a(n) = 6*a(n-1) -11*a(n-2) +a(n-3) +16*a(n-4) -10*a(n-5) -7*a(n-6) +6*a(n-7) +a(n-8) -a(n-9).

Empirical g.f.: x*(32 - 79*x + 143*x^3 - 89*x^4 - 61*x^5 + 55*x^6 + 6*x^7 - 9*x^8) / ((1 - x)^2*(1 - x - x^2)^2*(1 - 2*x - x^2 + x^3)). - Colin Barker, Jun 04 2018

EXAMPLE

Some solutions for n=4:

..2..2....1..1....2..1....0..1....0..2....1..2....2..0....1..0....0..2....0..2

..2..2....0..2....1..2....2..2....0..2....1..2....0..2....0..2....2..0....0..2

..2..2....2..0....1..2....2..2....2..0....1..2....1..2....2..2....0..2....2..2

..2..2....0..2....1..2....2..2....0..2....1..2....1..2....2..2....1..2....2..2

..2..2....0..2....1..2....2..2....1..2....1..2....1..2....2..2....1..2....2..2

CROSSREFS

Cf. A203728.

Sequence in context: A044283 A044664 A221685 * A231527 A298201 A234443

Adjacent sequences:  A203718 A203719 A203720 * A203722 A203723 A203724

KEYWORD

nonn

AUTHOR

R. H. Hardin, Jan 05 2012

STATUS

approved

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Last modified August 13 22:39 EDT 2022. Contains 356109 sequences. (Running on oeis4.)