%I A001052 M0911 N0343
%S A001052 1,2,3,11,69,701,10584,222965,6253604,225352709,10147125509,
%T A001052 558317255704,36859086001973,2875567025409598,261713458398275391,
%U A001052 27482788698844325653,3298196357319717353751,448582187384180404435789
%N A001052 a(n) = n(n-1)a(n-1)/2 + a(n-2).
%D A001052 N. J. A. Sloane, A Handbook of Integer Sequences, Academic Press, 1973 
               (includes this sequence).
%D A001052 N. J. A. Sloane and Simon Plouffe, The Encyclopedia of Integer Sequences, 
               Academic Press, 1995 (includes this sequence).
%o A001052 (PARI) a(n)=if(n<2,max(0,n+1),n*(n-1)*a(n-1)/2+a(n-2))
%Y A001052 Sequence in context: A105217 A066046 A065597 this_sequence A155187 A109132 
               A008510
%Y A001052 Adjacent sequences: A001049 A001050 A001051 this_sequence A001053 A001054 
               A001055
%K A001052 nonn,easy
%O A001052 0,2
%A A001052 N. J. A. Sloane (njas(AT)research.att.com).
%E A001052 More terms from James A. Sellers (sellersj(AT)math.psu.edu), Sep 19 2000