A248918 a(n) = index of (n+1)-th prime power in A247665.

1, 2, 3, 4, 5, 7, 6, 8, 9, 31, 10, 11, 12, 27, 28, 14, 16, 63, 17, 18, 19, 20, 32, 21, 22, 23, 127, 24, 25, 26, 29, 115, 30, 33, 34, 35, 36, 37, 38, 39, 40, 111, 41, 255, 42, 43, 44, 45, 46, 47, 48, 49, 50, 51, 52, 53, 54, 56, 58, 59, 60, 61, 62, 64, 66, 67

Offset: 1

Author

Reinhard Zumkeller, Oct 16 2014

Keywords

• nonn

Crossrefs

Cf. A248387 (subsequence), A000961.

Programs

Haskell

import Data.List (elemIndex); import Data.Maybe (fromJust)
a248918 = (+ 1) . fromJust . (`elemIndex` a247665_list) . a000961 . (+ 1)