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If a(n) is prime then it is not in A000043. [Alonso del Arte, Oct 07 2011]
Table of n, a(n) for n=1..47.
Select[Range[0, 49], PrimePi[2^# - # - 1] == PrimePi[2^# + #] &] (* Alonso del Arte, Oct 07 2011 *)
Sequence in context: A239523 A129820 A096522 * A015734 A221617 A083806
Adjacent sequences: A195348 A195349 A195350 * A195352 A195353 A195354
Juri-Stepan Gerasimov, Sep 16 2011