Sum{T(n-k,k)}, 0<=k<=[ n/2 ], T given by A026681.

Terms

a(0) =1a(1) =1a(2) =2a(3) =4a(4) =7a(5) =13a(6) =21a(7) =36a(8) =58a(9) =106a(10) =182a(11) =333a(12) =553a(13) =964a(14) =1583a(15) =2842a(16) =4851a(17) =8752a(18) =14662a(19) =25624a(20) =42578a(21) =75838a(22) =129440a(23) =231437a(24) =389828a(25) =680953a(26) =1140225a(27) =2019932a(28) =3451406a(29) =6132335