a(n) = T(n,0) + T(n,1) + ... + T(n,[ n/2 ]), T given by A026648.

Terms

a(0) =1a(1) =1a(2) =4a(3) =5a(4) =15a(5) =22a(6) =67a(7) =98a(8) =275a(9) =436a(10) =1249a(11) =1940a(12) =5244a(13) =8632a(14) =23896a(15) =38408a(16) =101419a(17) =170896a(18) =462361a(19) =760400a(20) =1975160a(21) =3383392a(22) =9001276a(23) =15054368a(24) =38623130a(25) =66984256a(26) =175903414a(27) =298045760a(28) =757228832a(29) =1326151552