Index of 2^n in A109812.

Terms

a(0) =1a(1) =2a(2) =3a(3) =5a(4) =8a(5) =15a(6) =29a(7) =50a(8) =103a(9) =164a(10) =417a(11) =649a(12) =1324a(13) =2684a(14) =5348a(15) =10226a(16) =21298a(17) =41538a(18) =84652a(19) =165034a(20) =322262a(21) =646648a(22) =1283556a(23) =2584860a(24) =5163368a(25) =10271638a(26) =20566708a(27) =40308350a(28) =80758553a(29) =161522919