Least k such that at least half of the last n digits of 2^k are 9.

Terms

a(0) =12a(1) =53a(2) =53a(3) =232a(4) =93a(5) =1862a(6) =93a(7) =3244a(8) =93a(9) =93a(10) =93a(11) =55754a(12) =12864a(13) =55756a(14) =23353a(15) =361353a(16) =16441a(17) =361353a(18) =304362a(19) =361353a(20) =361353a(21) =361353a(22) =361353a(23) =3748854a(24) =3748854a(25) =78055893a(26) =66290232a(27) =119133355a(28) =119133355a(29) =379371432