The OEIS Foundation is grateful to everyone who made a donation during our Annual Appeal. Visit the new and spectacular Pictures from the OEIS page!
1,2
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.
A192454(a(n))=0.
Select[Range[0, 49], PrimePi[2^# - # - 1] == PrimePi[2^# + #] &] (* Alonso del Arte, Oct 07 2011 *)
Cf. A192454
Sequence in context: A239523 A129820 A096522 * A015734 A221617 A083806
Adjacent sequences: A195348 A195349 A195350 * A195352 A195353 A195354
nonn
Juri-Stepan Gerasimov, Sep 16 2011
approved