%I A001697 M1902 N0751
%S A001697 1,1,2,8,96,10368,108615168,11798392572168192,
%T A001697 139202068568601556987554268864512,
%U A001697 19377215893777651167043206536157390321290709180447278572301746176
%N A001697 a(n+1)=a(n)(a(0)+ ... +a(n)).
%C A001697 Number of binary trees of height n where for each node the left subtree 
               is at least as high as the right subtree. - Franklin T. Adams-Watters, 
               Feb 08 2007
%D A001697 N. J. A. Sloane and Simon Plouffe, The Encyclopedia of Integer Sequences, 
               Academic Press, 1995 (includes this sequence).
%D A001697 N. J. A. Sloane, A Handbook of Integer Sequences, Academic Press, 1973 
               (includes this sequence).
%H A001697 A. V. Aho and N. J. A. Sloane, <a href="http://www.research.att.com/~njas/
               doc/doubly.html">Some doubly exponential sequences</a>, Fib. Quart., 
               11 (1973), 429-437.
%o A001697 (PARI) a(n)=if(n<2,n >= 0,a(n-1)^2*(1+1/a(n-2)))
%Y A001697 a(n)=A039941(2*n+1); first difference sequence of A001696 is this sequence.
%Y A001697 Cf. A002658, A001699.
%Y A001697 Sequence in context: A137704 A001417 A156926 this_sequence A006069 A052457 
               A119654
%Y A001697 Adjacent sequences: A001694 A001695 A001696 this_sequence A001698 A001699 
               A001700
%K A001697 nonn,easy,nice
%O A001697 0,3
%A A001697 N. J. A. Sloane (njas(AT)research.att.com).
%E A001697 Additional comments from Michael Somos, May 19, 2000