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%I #3 Mar 30 2012 16:50:20
%S 1,2,9,216,174960,146932807680,125937291507579224064000,
%T 108755666689817047890109782510255885778944000000,
%U 93143885917529328515023382841413836868525118214478405334515136630707122998865821696000000000000
%N a(1)=1, a(2)=2, a(3)=9; a(n) = n*(n - 2)*a(n - 1)^2/(n - 1).
%C Lower bound to number of perfect Morse matchings of n-simplex.
%D M. K. Chari and M. Joswig, Complexes of discrete Morse functions, Disc. Math. 302 (2005), 39-51.
%Y Cf. A005271.
%K nonn
%O 1,2
%A _N. J. A. Sloane_, Dec 01 2005
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