A173888 Exactly one of (2^n-1)^2-2 and (2^n+1)^2-2 is prime.

0, 1, 4, 5, 6, 7, 8, 9, 10, 17, 19, 23, 25, 32, 51, 55, 65, 87, 129, 132, 159, 171, 175, 180, 242, 315, 324, 358, 393, 435, 467, 491, 501, 507, 555, 591, 680, 786, 800, 1070, 1459, 1650, 1707, 2813, 2923, 3281, 4217, 5153, 6287, 6365, 6462, 10088, 10367, 14289

Offset

1,3

Comments

The numbers which are in A091513 or A091515, but not in both sequences. [From R. J. Mathar, Mar 09 2010]

Links

Table of n, a(n) for n=1..54.

Example

a(1)=1 because (2^1-1)^2-2=-1 is nonprime and (2^1+1)^2-2=7 is prime.

Crossrefs

Cf. A091513, A091515, A091514, A091516.

Sequence in context: A039091 A189817 A214420 * A341051 A120181 A016070

Adjacent sequences: A173885 A173886 A173887 * A173889 A173890 A173891

Keyword

nonn

Author

Juri-Stepan Gerasimov, Mar 01 2010

Extensions

Corrected (0 inserted, 12, 16, 18, 21 removed) and extended by R. J. Mathar, Mar 09 2010

Status

approved