a(n) = 2^(n - 1) (n - mod(n, 2)).

Terms

a(0) =0a(1) =4a(2) =8a(3) =32a(4) =64a(5) =192a(6) =384a(7) =1024a(8) =2048a(9) =5120a(10) =10240a(11) =24576a(12) =49152a(13) =114688a(14) =229376a(15) =524288a(16) =1048576a(17) =2359296a(18) =4718592a(19) =10485760a(20) =20971520a(21) =46137344a(22) =92274688a(23) =201326592a(24) =402653184a(25) =872415232a(26) =1744830464a(27) =3758096384a(28) =7516192768a(29) =16106127360