A multiplicative version of 2^n - 1 (A000225).

Terms

a(0) =1a(1) =3a(2) =7a(3) =15a(4) =31a(5) =21a(6) =127a(7) =255a(8) =511a(9) =93a(10) =2047a(11) =105a(12) =8191a(13) =381a(14) =217a(15) =65535a(16) =131071a(17) =1533a(18) =524287a(19) =465a(20) =889a(21) =6141a(22) =8388607a(23) =1785a(24) =33554431a(25) =24573a(26) =134217727a(27) =1905a(28) =536870911a(29) =651