Duplicate of A083706.

Terms

a(0) =1a(1) =4a(2) =9a(3) =18a(4) =35a(5) =68a(6) =133a(7) =262a(8) =519a(9) =1032a(10) =2057a(11) =4106a(12) =8203a(13) =16396a(14) =32781a(15) =65550a(16) =131087a(17) =262160a(18) =524305a(19) =1048594a(20) =2097171a(21) =4194324a(22) =8388629a(23) =16777238a(24) =33554455a(25) =67108888a(26) =134217753a(27) =268435482a(28) =536870939a(29) =1073741852