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 A092238 Number of ways to write the permutation n,n-1,...,1 of 1,2,...,n as a product of n(n-1)/2 transpositions, where each transposition of 1,2,...,n occurs exactly once. 0
 1, 1, 1, 2, 64, 59712, 3580519776 (list; graph; refs; listen; history; text; internal format)
 OFFSET 0,4 COMMENTS If we impose the additional condition on the product t_1 t_2 ... of transpositions that the number of inversions increases by one each time we multiply by a t_i, then the number of ways is given by A005118. LINKS EXAMPLE a(3)=2 because 321 = (1,2)(1,3)(2,3) = (2,3)(1,3)(1,2). CROSSREFS Cf. A005118. Sequence in context: A085535 A060613 A139772 * A228252 A339305 A337651 Adjacent sequences:  A092235 A092236 A092237 * A092239 A092240 A092241 KEYWORD more,nonn AUTHOR Richard Stanley, Feb 19 2004 EXTENSIONS a(0)=1 prepended and a(6) added by Alois P. Heinz, Jul 12 2017 STATUS approved

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Last modified January 17 23:09 EST 2021. Contains 340249 sequences. (Running on oeis4.)