A088486 Primes p of the form k*(k + 1) - 1 such that p and p + 2 are twin primes.

5, 11, 29, 41, 71, 239, 419, 461, 599, 1481, 1721, 2549, 2969, 3539, 4421, 8009, 10301, 17291, 19181, 20021, 23561, 24179, 27059, 31151, 35531, 41411, 42641, 43889, 46439, 47741, 53591, 55931, 60761, 83231, 84389, 95789, 98909, 123551, 143261, 156419, 164429

Offset

1,1

Comments

a(n) + 1 is an oblong number (A002378). - Michel Marcus, Feb 04 2017

Links

Amiram Eldar, Table of n, a(n) for n = 1..10000

Formula

a(n) = A088485(n)*(A088485(n) + 1) - 1. - R. J. Mathar, Nov 14 2009

Example

20*20 + 20 - 1 = 419, 419 and 421 twin primes, 419 is the 7th of the sequence for k = 20.

Crossrefs

Cf. A002378, A088485.

Sequence in context: A141785 A144311 A074367 * A174917 A214451 A340544

Adjacent sequences: A088483 A088484 A088485 * A088487 A088488 A088489

Keyword

nonn

Author

Pierre CAMI, Nov 09 2003

Extensions

Sign in definition corrected by R. J. Mathar, Nov 13 2009

Status

approved