Search: id:A050166 Results 1-1 of 1 results found. %I A050166 %S A050166 1,1,2,1,4,5,1,6,14,14,1,8,27,48,42,1,10,44,110,165,132,1,12,65,208, %T A050166 429,572,429,1,14,90,350,910,1638,2002,1430,1,16,119,544,1700,3808, %U A050166 6188,7072,4862,1,18,152,798,2907,7752,15504,23256,15194,16796,1,20 %N A050166 Triangle T(n,k)=M(2n,k,-1), 0<=k<=n, n >= 0, array M as in A050144. %C A050166 Sometimes called Catalan's triangle, although this term is usually reserved for several other triangles! %C A050166 T is a mirror image of the array in A039598. %C A050166 Given (1) = row 0, then the sum of terms with alternating signs in row r of A050166 = (-1)^r * A000108(n); where A000108 = 1, 1, 2, 5, 14, 42...the Catalan numbers. - Herb Conn, HCR 83, Box 93, Custer, SD 57730 %C A050166 The diagonals of this triangle are self-convolutions of the main diagonal A000108(n+1) : 1, 2, 5, 14, 42, 132, 429, . . . - Philippe DELEHAM (kolotoko(AT)wanadoo.fr), May 25 2005 %D A050166 B. A. Bondarenko, Generalized Pascal Triangles and Pyramids (in Russian), FAN, Tashkent, 1990, ISBN 5-648-00738-8. English translation published by Fibonacci Association, Santa Clara Univ., Santa Clara, CA, 1993; see p. 29. %D A050166 E. H. M. Brietzke, An identity of Andrews ..., Discrete Math., 308 (2008), 4246-4262. %D A050166 E. Deutsch and L. Shapiro, A survey of the Fine numbers, Discrete Math., 241 (2001), 241-265. %D A050166 A. Nkwanta, Lattice paths and RNA secondary structures, in African Americans in Mathematics, ed. N. Dean, Amer. Math. Soc., 1997, pp. 137-147. %H A050166 R. K. Guy, Catwalks, Sandsteps and Pascal Pyramids, J. Integer Seqs., Vol. 3 (2000), #00.1.6 %F A050166 a(n, k) = C(2n+1, k)*2*(n-k+1)/(2n-k+2) = A039598(n, n-k) = a(n-1, k)+2*a(n-1, k-1)+a(n-1, k-2) [with a(0, 0) = 1 and a(n, k) = 0 if n<0 or n