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Twice A002437.
1

%I #2 Mar 30 2012 16:51:15

%S 2,14,610,66734,13631170,4474847054,2154541552930,1430306187579374,

%T 1252111529306645890,1397549490970710103694,1937106722774840873390050,

%U 3264361741756845694953780014,6572644038805857912224455865410,15583184923914619905634967412688334,42971525874172716914734880462487351970

%N Twice A002437.

%C Suggested by analogy with A000191.

%p Q:=proc(n) option remember; if n=0 then RETURN(1); else RETURN(expand((u^2+1)*diff(Q(n-1),u)+u*Q(n-1))); fi; end;

%p [seq(2*subs(u=sqrt(3),Q(2*n)),n=0..25)];

%K nonn

%O 0,1

%A _N. J. A. Sloane_, Nov 06 2009