"Email this user" was broken Aug 14 to 9am Aug 16. If you sent someone a message in this period, please send it again.
P. Ribenboim, The Book of Prime Number Records. Springer-Verlag, NY, 2nd ed., 1989, p. 81.
N. J. A. Sloane and Simon Plouffe, The Encyclopedia of Integer Sequences, Academic Press, 1995 (includes this sequence).
Table of n, a(n) for n=0..3.
Subsequence of A007013.
Sequence in context: A128071 A079622 A182330 * A156521 A012636 A006031
Adjacent sequences: A005841 A005842 A005843 * A005845 A005846 A005847