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 A173424 Triangle T(n,m) read by rows: (2*n - 2*m)!*(2*m)!/( 2^n*(n - m)!*m! ) 0
 1, 1, 1, 3, 1, 3, 15, 3, 3, 15, 105, 15, 9, 15, 105, 945, 105, 45, 45, 105, 945, 10395, 945, 315, 225, 315, 945, 10395, 135135, 10395, 2835, 1575, 1575, 2835, 10395, 135135, 2027025, 135135, 31185, 14175, 11025, 14175, 31185, 135135, 2027025, 34459425 (list; table; graph; refs; listen; history; text; internal format)
 OFFSET 0,4 COMMENTS Row sums are: 1, 2, 7, 36, 249, 2190, 23535, 299880, 4426065, 74294010, 1397669175, ..., apparently A034430. LINKS FORMULA T(n,m)= A006882(2*n-2*m-1)* A006882(2*m-1) = A001147(n-m)*A001147(m). EXAMPLE 1; 1, 1; 3, 1, 3; 15, 3, 3, 15; 105, 15, 9, 15, 105; 945, 105, 45, 45, 105, 945; 10395, 945, 315, 225, 315, 945, 10395; 135135, 10395, 2835, 1575, 1575, 2835, 10395, 135135; 2027025, 135135, 31185, 14175, 11025, 14175, 31185, 135135, 2027025; 34459425, 2027025, 405405, 155925, 99225, 99225, 155925, 405405, 2027025, 34459425; 654729075, 34459425, 6081075, 2027025, 1091475, 893025, 1091475, 2027025, 6081075, 34459425, 654729075; MATHEMATICA t[n_, m_] = (2*n - 2*m)!*(2*m)!/(2^n*(n - m)!*m!); Table[Table[t[n, m], {m, 0, n}], {n, 0, 10}]; Flatten[%] CROSSREFS Sequence in context: A001351 A216021 A327149 * A143081 A179658 A112811 Adjacent sequences:  A173421 A173422 A173423 * A173425 A173426 A173427 KEYWORD nonn,tabl AUTHOR Roger L. Bagula, Feb 18 2010 EXTENSIONS Formula added by the Assoc. Editors of the OEIS, Feb 24 2010 STATUS approved

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Last modified December 8 18:37 EST 2019. Contains 329865 sequences. (Running on oeis4.)