Least positive number k such that 2^k mod k = 2n, or 0 if no such k exists.

Terms

a(0) =1a(1) =3a(2) =6a(3) =10669a(4) =9a(5) =18a(6) =3763a(7) =1010a(8) =20a(9) =35a(10) =2951a(11) =42a(12) =50a(13) =27a(14) =36a(15) =49a(16) =56a(17) =110a(18) =697a(19) =578a(20) =156a(21) =540923a(22) =70a(23) =287a(24) =104a(25) =147a(26) =4044a(27) =970a(28) =220a(29) =59378