a(0)=1; a(1)=2; a(n) = a(n-1) + a(n-2)*(3 - (-1)^n)/2.

Terms

a(0) =1a(1) =2a(2) =3a(3) =7a(4) =10a(5) =24a(6) =34a(7) =82a(8) =116a(9) =280a(10) =396a(11) =956a(12) =1352a(13) =3264a(14) =4616a(15) =11144a(16) =15760a(17) =38048a(18) =53808a(19) =129904a(20) =183712a(21) =443520a(22) =627232a(23) =1514272a(24) =2141504a(25) =5170048a(26) =7311552a(27) =17651648a(28) =24963200a(29) =60266496