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 A203446 Number of (n+1) X 3 0..1 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) such that rows of b(i,j) and columns of c(i,j) are lexicographically nondecreasing. 1
 16, 34, 80, 174, 376, 786, 1624, 3310, 6704, 13506, 27136, 54414, 109000, 218194, 436616, 873486, 1747264, 3494850, 6990064, 13980526, 27961496, 55923474, 111847480, 223695534, 447391696, 894784066, 1789568864, 3579138510 (list; graph; refs; listen; history; text; internal format)
 OFFSET 1,1 COMMENTS Column 2 of A203452. LINKS R. H. Hardin, Table of n, a(n) for n = 1..210 FORMULA Empirical: a(n) = 4*a(n-1) -4*a(n-2) -2*a(n-3) +5*a(n-4) -2*a(n-5). Empirical g.f.: 2*x*(8 - 15*x + 4*x^2 + 11*x^3 - 6*x^4) / ((1 - x)^3*(1 + x)*(1 - 2*x)). - Colin Barker, Jun 04 2018 EXAMPLE Some solutions for n=10: ..0..0..1....0..0..0....0..0..1....0..0..1....1..0..1....0..0..0....0..0..0 ..0..0..1....0..0..0....0..0..1....0..0..1....0..1..0....0..0..1....0..0..0 ..0..1..0....0..0..1....0..0..1....0..0..1....1..0..1....0..0..1....0..0..0 ..1..0..1....0..1..0....0..0..1....0..0..1....0..1..0....0..0..1....0..0..0 ..1..0..1....1..0..1....0..0..1....0..1..0....1..0..1....0..1..0....0..0..1 ..1..0..1....0..1..0....0..1..0....0..1..0....0..1..0....1..0..1....0..1..1 ..0..1..0....0..1..0....1..0..1....0..1..0....1..0..1....1..0..1....0..1..1 ..0..1..0....1..1..0....0..1..1....0..1..0....0..1..1....0..1..0....1..1..0 ..0..1..0....1..1..0....0..1..1....0..1..1....1..1..1....0..1..0....1..1..0 ..0..1..0....1..1..0....1..1..1....0..1..1....1..1..1....0..1..0....1..1..0 ..0..1..1....1..1..0....1..1..1....0..1..1....1..1..1....1..1..0....1..1..1 CROSSREFS Cf. A203452. Sequence in context: A350522 A132760 A209377 * A153819 A185459 A279712 Adjacent sequences: A203443 A203444 A203445 * A203447 A203448 A203449 KEYWORD nonn AUTHOR R. H. Hardin, Jan 02 2012 STATUS approved

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Last modified September 23 19:57 EDT 2023. Contains 365554 sequences. (Running on oeis4.)