%I A025240
%S A025240 3,2,6,22,90,394,1806,8558,41586,206098,1037718,5293446,27297738,142078746,
%T A025240 745387038,3937603038,20927156706,111818026018,600318853926,3236724317174,
%U A025240 17518619320890,95149655201962,518431875418926,2832923350929742
%N A025240 a(n) = a(1)*a(n-1) + a(2)*a(n-2) + ...+ a(n-2)*a(2) for n >= 3.
%F A025240 G.f.: (1+3*x-sqrt(1-6*x+x^2))/2 - Michael Somos, Jun 08, 2000.
%o A025240 (PARI) a(n)=polcoeff((1+3*x-sqrt(1-6*x+x^2+x*O(x^n)))/2,n)
%Y A025240 Essentially same as A006318.
%Y A025240 Sequence in context: A082561 A110768 A140230 this_sequence A137602 A018864 
               A019951
%Y A025240 Adjacent sequences: A025237 A025238 A025239 this_sequence A025241 A025242 
               A025243
%K A025240 nonn
%O A025240 1,1
%A A025240 Clark Kimberling (ck6(AT)evansville.edu)