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A005769
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Number of convex polygons of length 2n on square lattice whose left-most bottom vertex is strictly to the right of the right-most top vertex.
(Formerly M4911)
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3
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1, 13, 110, 758, 4617, 25895, 136949, 693369, 3395324, 16197548, 75675657, 347624505, 1574756959, 7051383905, 31266981002, 137492793602, 600295660953, 2604690331787
(list; graph; refs; listen; history; internal format)
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OFFSET
| 6,2
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REFERENCES
| M.-P. Delest and G. Viennot, Algebraic languages and polyominoes enumeration, Theoretical Computer Sci., 34 (1984), 169-206.
N. J. A. Sloane and Simon Plouffe, The Encyclopedia of Integer Sequences, Academic Press, 1995 (includes this sequence).
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FORMULA
| G.f. x^4*(2-20*x+75*x^2-127*x^3+95*x^4-27*x^5+4*x^6)/((1-2*x^(1/2))^2*(1+2*x^(1/2))^2*(1-2*x)*(1+x^(1/2)-x)^2*(1-x^(1/2)-x)^2)-2*x^4*(1-4*x)^(-3/2) - Markus Voege (voege(AT)blagny.inria.fr), Nov 28 2003
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CROSSREFS
| A005436(n) = A005768(n) + a(n) + A005770(n)
Sequence in context: A055840 A163845 A075143 * A042941 A021344 A119744
Adjacent sequences: A005766 A005767 A005768 * A005770 A005771 A005772
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KEYWORD
| nonn
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AUTHOR
| Simon Plouffe (simon.plouffe(AT)gmail.com)
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EXTENSIONS
| Better description from Markus Voege (voege(AT)blagny.inria.fr), Nov 28 2003
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