Search: id:A001471
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%I A001471 M1833 N0727
%S A001471 0,0,0,2,8,20,80,350,1232,5768,31040,142010,776600,4874012,27027728,
%T A001471 168369110,1191911840,7678566800,53474964992,418199988338,
%U A001471 3044269834280,23364756531620,199008751634000,1605461415071822
%N A001471 Number of degree-n permutations of order exactly 3.
%D A001471 N. J. A. Sloane and Simon Plouffe, The Encyclopedia of Integer Sequences, 
               Academic Press, 1995 (includes this sequence).
%D A001471 N. J. A. Sloane, A Handbook of Integer Sequences, Academic Press, 1973 
               (includes this sequence).
%D A001471 L. Moser and M. Wyman, On solutions of x^d = 1 in symmetric groups, Canad. 
               J. Math., 7 (1955), 159-168.
%H A001471 T. D. Noe, <a href="b001471.txt">Table of n, a(n) for n=0..100</a>
%F A001471 a(n) = a(n-1)+(1+a(n-3))*(n-1)(n-2) = Sum_{j = 1 to floor[n/3]}[n!/(j!*(n-3j)!*(3^j))] 
               = A001470(n)-1 - Henry Bottomley (se16(AT)btinternet.com), Jan 26 
               2001.
%F A001471 E.g.f.: -exp(x)+exp(x+1/3*x^3).
%Y A001471 Cf. A000085, A001470, A001472, A052501, A053496-A053505, A001189, A001471, 
               A001473, A061121-A061128.
%Y A001471 Sequence in context: A133467 A091004 A005559 this_sequence A162585 A000159 
               A090612
%Y A001471 Adjacent sequences: A001468 A001469 A001470 this_sequence A001472 A001473 
               A001474
%K A001471 nonn,easy,nice
%O A001471 0,4
%A A001471 N. J. A. Sloane (njas(AT)research.att.com) and J. H. Conway (conway(AT)math.princeton.edu)

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