a(n) = 16*(2^n - 1).

Terms

a(0) =0a(1) =16a(2) =48a(3) =112a(4) =240a(5) =496a(6) =1008a(7) =2032a(8) =4080a(9) =8176a(10) =16368a(11) =32752a(12) =65520a(13) =131056a(14) =262128a(15) =524272a(16) =1048560a(17) =2097136a(18) =4194288a(19) =8388592a(20) =16777200a(21) =33554416a(22) =67108848a(23) =134217712a(24) =268435440a(25) =536870896a(26) =1073741808a(27) =2147483632a(28) =4294967280a(29) =8589934576