Index of first occurrence of n in A281579, or -1 if n does not appear there..

Terms

a(0) =1a(1) =3a(2) =6a(3) =7a(4) =15a(5) =16a(6) =34a(7) =240a(8) =241a(9) =317a(10) =502a(11) =503a(12) =504a(13) =505a(14) =1077a(15) =1178a(16) =1179a(17) =1806a(18) =4866a(19) =4901a(20) =4902a(21) =4946a(22) =4947a(23) =8195a(24) =8196a(25) =8197a(26) =8198a(27) =8199a(28) =8200a(29) =8201