p-INVERT of (0,1,0,1,0,1,...), where p(S) = 1 - 2 S - 2 S^2.

Terms

a(0) =2a(1) =6a(2) =18a(3) =56a(4) =170a(5) =522a(6) =1594a(7) =4880a(8) =14922a(9) =45654a(10) =139642a(11) =427176a(12) =1306690a(13) =3997146a(14) =12227058a(15) =37402144a(16) =114411538a(17) =349980390a(18) =1070575586a(19) =3274847512a(20) =10017625050a(21) =30643508586a(22) =93737246762a(23) =286738430256a(24) =877121205338