A173097 - OEIS

%I #4 Sep 10 2016 13:47:04

%S 1,2,3,10,57,1130,128763,291003250,74940902830737,

%T 43616092563357042787250,6537258709293941644669222566000575763,

%U 570259361950353096439107826720562074995499493885695588056250

%N a(1)=1, a(2)=2, a(n)=2*a(n-2)*a(n-1)-a(n-2).

%t a=1;b=2;lst={a,b};Do[c=2*a*b-a;AppendTo[lst,c];a=b;b=c,{n,11}];lst

%t RecurrenceTable[{a[1]==1,a[2]==2,a[n]==2a[n-2]a[n-1]-a[n-2]},a,{n,15}] (* _Harvey P. Dale_, Sep 10 2016 *)

%Y Cf. A173093, A173094, A173096

%K nonn

%O 1,2

%A _Vladimir Joseph Stephan Orlovsky_, Feb 09 2010