%I A087205
%S A087205 1,2,0,8,16,64,192,640,2048,6656,21504,69632,225280,729088,2359296,
%T A087205 7634944,24707072,79953920,258736128,837287936,2709520384,8768192512,
%U A087205 28374466560,91821703168,297141272576,961569357824,3111703805952
%V A087205 1,2,0,8,-16,64,-192,640,-2048,6656,-21504,69632,-225280,729088,-2359296,
               7634944,
%W A087205 -24707072,79953920,-258736128,837287936,-2709520384,8768192512,-28374466560,
%X A087205 91821703168,-297141272576,961569357824,-3111703805952
%N A087205 a(n)=-2a(n-1)+4a(n-2), a(0)=1,a(1)=2.
%C A087205 Inverse binomial transform of A087204. a(n+2)=A085449(n)*(-1)^(n+1); 
               a(n+3)=A063727(n)*(-1)^n.
%F A087205 a(n)=(-1-sqrt(5))^n(1/2-3sqrt(5)/10)+(-1+sqrt(5))^n(1/2+3sqrt(5)/10).
%Y A087205 Cf. A084222.
%Y A087205 Sequence in context: A120559 A120555 A128063 this_sequence A062134 A002909 
               A118437
%Y A087205 Adjacent sequences: A087202 A087203 A087204 this_sequence A087206 A087207 
               A087208
%K A087205 easy,sign
%O A087205 0,2
%A A087205 Paul Barry (pbarry(AT)wit.ie), Aug 25 2003