A174131 Either 2*n^2-+11 is a prime.

0, 1, 2, 4, 5, 7, 8, 10, 12, 13, 16, 18, 19, 20, 23, 24, 27, 28, 29, 31, 37, 41, 43, 46, 48, 49, 50, 52, 60, 62, 65, 70, 71, 72, 78, 83, 85, 87, 90, 91, 94, 95, 96, 98, 100, 105, 106, 108, 109, 111, 117, 120, 123, 124, 126, 128, 130, 134, 136, 137, 139, 145, 146, 147, 151

Offset

1,3

Links

Table of n, a(n) for n=1..65.

Example

a(1)=0 because 2*0^2-11=-11=nonprime and 2*0^2+11=11=prime; a(2)=1 because 2*1^2-11=-9=nonprime and 2*1^2+11=13=prime; a(3)=2 because 2*2^2-11=-3=nonprime and 2*2^2+11=19=prime; a(4)=4 because 2*4^2-11=21=nonprime and 2*4^2+11=43=prime.

Crossrefs

Cf. A050265, A092968.

Sequence in context: A047496 A223735 A123663 * A014248 A174799 A248566

Adjacent sequences: A174128 A174129 A174130 * A174132 A174133 A174134

Keyword

nonn

Author

Juri-Stepan Gerasimov, Mar 09 2010

Extensions

Corrected (15 removed) and extended beyond 71 by R. J. Mathar, Apr 20 2010

Status

approved