Search: id:A005789 Results 1-1 of 1 results found. %I A005789 M3997 %S A005789 1,5,42,462,6006,87516,1385670,23371634,414315330,7646001090, %T A005789 145862174640,2861142656400,57468093927120,1178095925505960, %U A005789 24584089974896430,521086299271824330,11198784501894470250 %N A005789 3-dimensional Catalan numbers. %C A005789 Number of standard tableaux of shape (n,n,n). - Emeric Deutsch (deutsch(AT)duke.poly.edu), May 13 2004 %C A005789 Number of up-down permutations of length 2n with no four-term increasing subsequence, or equivalently the number of down-up permutations of length 2n with no four-term decreasing subsequence. (An up-down permutation is one whose descent set is {2, 4, 6, ...}.) [From Joel Brewster Lewis (jblewis(AT)post.harvard.edu), Oct 04 2009] %D A005789 N. J. A. Sloane and Simon Plouffe, The Encyclopedia of Integer Sequences, Academic Press, 1995 (includes this sequence). %D A005789 Snover, Stephen L.; and Troyer, Stephanie F.; A four-dimensional Catalan formula. Proceedings of the Nineteenth Manitoba Conference on Numerical Mathematics and Computing (Winnipeg, MB, 1989). Congr. Numer. 75 (1990), 123-126. %D A005789 R. A. Sulanke, Generalizing Narayana and Schroeder Numbers to Higher Dimensions, Electron. J. Combin. 11 (2004), Research Paper 54, 20 pp. %H A005789 R. A. Sulanke, Three-dimensional Narayana and Schr\"oder numbers %H A005789 J. B. Lewis, Pattern avoidance and RSK-like algorithms for alternating permutations and Young tableaux [From Joel Brewster Lewis (jblewis(AT)post.harvard.edu), Oct 04 2009] %F A005789 a(n) = 2*(3*n)!/(n!*(n+1)!*(n+2)!); a(n) = 0!*1!*..*(k-1)! *(k*n)! / ( n!*(n+1)!*..*(n+k-1)! ) for k=3. %F A005789 G.f. (1/30)*(1/x-27)*(9*hypergeom([1/3, 2/3],[1],27*x)+(216*x+1)*hypergeom([4/ 3, 5/3],[2],27*x))-1/(3*x) [From Mark van Hoeij (hoeij(AT)math.fsu.edu), Oct 14 2009] %t A005789 (* first do *) Needs["DiscreteMath`Combinatorica`"] (* then *) Table[ NumberOfTableaux@ {n, n, n}], {n, 17}] (* Robert G. Wilson v Nov 15 2006 *) %Y A005789 A row of A060854. %Y A005789 Sequence in context: A082145 A126765 A024492 this_sequence A151334 A102693 A052654 %Y A005789 Adjacent sequences: A005786 A005787 A005788 this_sequence A005790 A005791 A005792 %K A005789 nonn,easy %O A005789 1,2 %A A005789 N. J. A. Sloane (njas(AT)research.att.com). Search completed in 0.001 seconds