a(n) = A389802(2n+1).

Terms

a(0) =1a(1) =2a(2) =3a(3) =6a(4) =11a(5) =20a(6) =41a(7) =74a(8) =141a(9) =258a(10) =473a(11) =828a(12) =1447a(13) =2472a(14) =4183a(15) =6976a(16) =11403a(17) =18332a(18) =29219a(19) =45842a(20) =71211a(21) =109510a(22) =166325a(23) =250256a(24) =372701a(25) =550526a(26) =804191a(27) =1167102a(28) =1676269a(29) =2393822