A243183 Primes of the form 2x^2+2xy+5y^2.

2, 5, 17, 29, 41, 53, 89, 101, 113, 137, 149, 173, 197, 233, 257, 269, 281, 293, 317, 353, 389, 401, 449, 461, 509, 521, 557, 569, 593, 617, 641, 653, 677, 701, 761, 773, 797, 809, 821, 857, 881, 929, 941, 953, 977, 1013, 1049, 1061, 1097, 1109, 1181, 1193, 1217, 1229, 1277, 1289, 1301, 1361, 1373, 1409, 1433, 1481, 1493, 1553, 1601, 1613, 1637

Offset

1,1

Comments

Because all terms in A243182 are in {0, 2, 5, 6, 8, 9} (mod 12) and 5 is the only one in this set coprime to 12, this is (apart from the 2) a subsequence of A040117. - R. J. Mathar, Jul 07 2023

This sequence is actually equal to A040117, except for the additional initial a(1) = 2 here (and indexing of the remaining terms). - M. F. Hasler, Jul 03 2025

Links

Table of n, a(n) for n=1..67.

N. J. A. Sloane et al., Binary Quadratic Forms and OEIS (Index to related sequences, programs, references)

Crossrefs

Primes in A243182.

Cf. A040117 (the same without the initial 2 here).

Sequence in context: A211548 A277208 A395567 * A195271 A077217 A120847

Adjacent sequences: A243180 A243181 A243182 * A243184 A243185 A243186

Keyword

nonn

Author

N. J. A. Sloane, Jun 02 2014

Status

approved