a(n) = (2^n - 1)*2^valuation(n, 2) for n > 0 and a(0) = 0.

Terms

a(0) =0a(1) =1a(2) =6a(3) =7a(4) =60a(5) =31a(6) =126a(7) =127a(8) =2040a(9) =511a(10) =2046a(11) =2047a(12) =16380a(13) =8191a(14) =32766a(15) =32767a(16) =1048560a(17) =131071a(18) =524286a(19) =524287a(20) =4194300a(21) =2097151a(22) =8388606a(23) =8388607a(24) =134217720a(25) =33554431a(26) =134217726a(27) =134217727a(28) =1073741820a(29) =536870911