Positions at which powers of 2 occur in A057929. (Or -1 if it does not occur.)

Terms

a(0) =-1a(1) =0a(2) =-1a(3) =2a(4) =5a(5) =11a(6) =23a(7) =32a(8) =47a(9) =83a(10) =131a(11) =239a(12) =311a(13) =527a(14) =731a(15) =965a(16) =1703a(17) =2675a(18) =3827a(19) =6359a(20) =9659a(21) =14555a(22) =23087a(23) =33041a(24) =45995a(25) =77519a(26) =120467a(27) =177635a(28) =252713a(29) =405317