a(n) = 64*(2^n - 1).

Terms

a(0) =0a(1) =64a(2) =192a(3) =448a(4) =960a(5) =1984a(6) =4032a(7) =8128a(8) =16320a(9) =32704a(10) =65472a(11) =131008a(12) =262080a(13) =524224a(14) =1048512a(15) =2097088a(16) =4194240a(17) =8388544a(18) =16777152a(19) =33554368a(20) =67108800a(21) =134217664a(22) =268435392a(23) =536870848a(24) =1073741760a(25) =2147483584a(26) =4294967232a(27) =8589934528a(28) =17179869120a(29) =34359738304