Greatest k such that k-th prime < twice n-th prime.

Terms

a(0) =2a(1) =3a(2) =4a(3) =6a(4) =8a(5) =9a(6) =11a(7) =12a(8) =14a(9) =16a(10) =18a(11) =21a(12) =22a(13) =23a(14) =24a(15) =27a(16) =30a(17) =30a(18) =32a(19) =34a(20) =34a(21) =37a(22) =38a(23) =40a(24) =44a(25) =46a(26) =46a(27) =47a(28) =47a(29) =48