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A162551
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2 * C(2*n,n-1).
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2
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0, 2, 8, 30, 112, 420, 1584, 6006, 22880, 87516, 335920, 1293292, 4992288, 19315400, 74884320, 290845350, 1131445440, 4407922860, 17194993200, 67156001220, 262564816800, 1027583214840, 4025232800160, 15780742227900, 61915399071552
(list; graph; refs; listen; history; internal format)
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OFFSET
| 0,2
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COMMENTS
| Total length of all Dyck paths of length 2n.
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LINKS
| Vincenzo Librandi, Table of n, a(n) for n = 0..200
Guo-Niu Han, Enumeration of Standard Puzzles
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FORMULA
| a(n)=2*A001791(n). [From R. J. Mathar, Jul 15 2009]
a(n) equals the diagonal element A(n,n) of matrix A whose element A(i,j)=A(i-1,j)+A(i,j-1) [From Carmine Suriano, May 10 2010]
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PROG
| (MAGMA) [2*n*Catalan(n): n in [0..30]]; // Vincenzo Librandi, Jul 19 2011
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CROSSREFS
| Cf. A162549.
Sequence in context: A199923 A077839 A052530 * A073663 A155116 A133915
Adjacent sequences: A162548 A162549 A162550 * A162552 A162553 A162554
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KEYWORD
| nonn
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AUTHOR
| Franklin T. Adams-Watters (FrankTAW(AT)Netscape.net), Jul 05 2009
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