%I A097514
%S A097514 1,1,1,2,6,17,53,205,871,3876,18820,99585,558847,3313117,20825145,
%T A097514 138046940,959298572,6974868139,52972352923,419104459913,3446343893607,
%U A097514 29405917751526,259930518212766,2376498296500063,22441988298860757
%N A097514 Number of partitions of an n-set without blocks of size 2.
%F A097514 a(n) = Sum_{k=0..floor(n/2)} (-1)^k*binomial(n, 2*k)*(2*k-1)!!*Bell(n-2*k). 
               E.g.f.: exp(exp(x)-1-x^2/2). More generally, e.g.f. for number of 
               partitions of an n-set which contain exactly q blocks of size p is 
               x^(p*q)/(q!*p!^q)*exp(exp(x)-1-x^p/p!).
%p A097514 g:=exp(exp(x)-1-x^2/2): gser:=series(g,x=0,31): 1,seq(n!*coeff(gser,x^n),
               n=1..29); (Deutsch)
%Y A097514 Cf. A000296.
%Y A097514 Sequence in context: A148451 A148452 A148453 this_sequence A108630 A161408 
               A150033
%Y A097514 Adjacent sequences: A097511 A097512 A097513 this_sequence A097515 A097516 
               A097517
%K A097514 easy,nonn
%O A097514 0,4
%A A097514 Vladeta Jovovic (vladeta(AT)eunet.rs), Aug 26 2004
%E A097514 More terms from Emeric Deutsch (deutsch(AT)duke.poly.edu), Nov 18 2004