A091931 - OEIS

A091931

Change the first bit to 0 in binary notation for the n-th prime.

0, 1, 1, 3, 3, 5, 1, 3, 7, 13, 15, 5, 9, 11, 15, 21, 27, 29, 3, 7, 9, 15, 19, 25, 33, 37, 39, 43, 45, 49, 63, 3, 9, 11, 21, 23, 29, 35, 39, 45, 51, 53, 63, 65, 69, 71, 83, 95, 99, 101, 105, 111, 113, 123, 1, 7, 13, 15, 21, 25, 27, 37, 51, 55, 57, 61, 75, 81, 91, 93, 97, 103

(list; graph; refs; listen; history; text; internal format)

OFFSET

1,4

COMMENTS

a(n) = A053645(A000040(n)).

LINKS

Harvey P. Dale, Table of n, a(n) for n = 1..1000

FORMULA

a(n) = A000040(n) - 2^(A035100(n)-1).

MATHEMATICA

FromDigits[Rest[IntegerDigits[#, 2]], 2]&/@Prime[Range[80]] (* Harvey P. Dale, Apr 20 2012 *)

PROG