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0, 1, 10, 69, 406, 2186, 11124, 54445, 259006, 1205790, 5519020, 24918306, 111250140, 492051124, 2159081192, 9409526397, 40766269774, 175707380630, 753876367356, 3221460111958, 13716223138388, 58210889582796
(list; graph; refs; listen; history; internal format)
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OFFSET
| 0,3
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REFERENCES
| A. Bernini, F. Disanto, R. Pinzani and S. Rinaldi, Permutations defining convex permutominoes, preprint, 2007.
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LINKS
| Vincenzo Librandi, Table of n, a(n) for n = 0..173
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FORMULA
| a(n) = (n+3)*4^n -(n+2)*binomial(2*n+3, n+1)/2, G.f. x*(c(x)/(1-4*x))^2, where c(x) = g.f. for Catalan numbers A000108.
a(n+1), n >= 0 is convolution of A000346 with itself; a(n+1), n >= 0 is convolution of Catalan numbers A000108 C(n+1), n >= 0 with A002697; a(-1)=0.
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PROG
| (MAGMA) [(n+3)*4^n -(n+2)*Binomial(2*n+3, n+1)/2: n in [0..25]]; // Vincenzo Librandi, Jun 09 2011
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CROSSREFS
| Cf. A000108, A000346, A008549, A000302, A002697.
Sequence in context: A026958 A026988 A081280 * A016273 A128737 A130548
Adjacent sequences: A038803 A038804 A038805 * A038807 A038808 A038809
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KEYWORD
| easy,nonn
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AUTHOR
| Wolfdieter Lang (wolfdieter.lang(AT)physik.uni-karlsruhe.de)
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