Search: id:A078485
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%I A078485
%S A078485 0,1,1,1,7,15,31,63,127,255,511,1023,2047,4095,8191,16383,32767,65535,
               131071,
%T A078485 262143,524287,1048575,2097151,4194303,8388607,16777215,33554431,67108863,
%U A078485 134217727,268435455,536870911,1073741823,2147483647,4294967295,8589934591
%N A078485 Number of irreducible indecomposable permutations of degree n.
%D A078485 M. D. Atkinson and T. Stitt, Restricted permutations and the wreath product, 
               Discrete Math., 259 (2002), 19-36.
%F A078485 2^(n-1)-1 for n>3. G.f.: x-2*x^3+x/(1-2*x)-x/(1-x).
%F A078485 (1, 7, 15, 31, 63,...) = row sums of triangle A134065. - Gary W. Adamson 
               (qntmpkt(AT)yahoo.com), Oct 06 2007
%Y A078485 Cf. A134065.
%Y A078485 Sequence in context: A117747 A137196 A120094 this_sequence A159695 A014001 
               A063592
%Y A078485 Adjacent sequences: A078482 A078483 A078484 this_sequence A078486 A078487 
               A078488
%K A078485 nonn
%O A078485 0,5
%A A078485 N. J. A. Sloane (njas(AT)research.att.com), Jan 04 2003

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