a(n) = Sum_{i=0..floor(n/2)} T(2i,n-2i) where T is A049615.

Terms

a(0) =0a(1) =0a(2) =2a(3) =3a(4) =9a(5) =11a(6) =22a(7) =26a(8) =43a(9) =49a(10) =74a(11) =82a(12) =115a(13) =126a(14) =168a(15) =184a(16) =239a(17) =256a(18) =322a(19) =343a(20) =421a(21) =449a(22) =544a(23) =574a(24) =683a(25) =720a(26) =846a(27) =889a(28) =1035a(29) =1081