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 A241590 Numerators of Postnikov's hook-length formula 2^n*(n+1)^(n-1)/n!. 2
 1, 2, 6, 64, 250, 1728, 67228, 2097152, 1062882, 80000000, 9431790764, 6115295232, 7168641576148, 64793042714624, 2562890625000, 1152921504606846976, 5724846103019631586, 666334875701477376, 21921547431139208743756, 16777216000000000000000, 164839190645167033716, 513039635408293850333052928 (list; graph; refs; listen; history; text; internal format)
 OFFSET 0,2 REFERENCES Alexander Postnikov. Permutohedra, associahedra, and beyond. in: Conference in Honor of Richard Stanley's Sixtieth Birthday, June 2004. International Mathematics Research Notices, 6:1026-1106, 2009. LINKS Matthew Wilson, Bruhat order on fixed-point-free involutions in the symmetric group, Electron. J. Combin., 21(2) (2014), #P2.20. EXAMPLE 1, 2, 6, 64/3, 250/3, 1728/5, 67228/45, 2097152/315, 1062882/35, 80000000/567, 9431790764/14175, 6115295232/1925, 7168641576148/467775, ... MAPLE t1:= [seq(2^n*(n+1)^(n-1)/n!, n=0..50)]: t2:=map(numer, t1); # A241590 t3:=map(denom, t1); # A241591 PROG (PARI) vector(30, n, n--; numerator(2^n*(n+1)^(n-1)/n!)) \\ Michel Marcus, Jul 18 2015 CROSSREFS Cf. A241591. Sequence in context: A082640 A139695 A347949 * A052522 A193609 A061999 Adjacent sequences:  A241587 A241588 A241589 * A241591 A241592 A241593 KEYWORD nonn,frac AUTHOR N. J. A. Sloane, May 13 2014 STATUS approved

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Last modified May 27 16:48 EDT 2022. Contains 354110 sequences. (Running on oeis4.)