A172070 Primes p such that either p-1/2-+5/2, but not both, is prime.

3, 11, 17, 29, 41, 59, 71, 101, 107, 137, 149, 179, 191, 197, 227, 239, 269, 281, 311, 347, 419, 431, 461, 521, 569, 599, 617, 641, 659, 809, 821, 827, 857, 881, 1019, 1031, 1049, 1061, 1091, 1151, 1229, 1277, 1289, 1301, 1319, 1427, 1451, 1481, 1487, 1607, 1619, 1667, 1697, 1721, 1787, 1871, 1877

Offset

1,1

Comments

Lesser of twin primes without 5.

Links

Table of n, a(n) for n=1..57.

Example

a(1)=3 because 3-1/2-5/2=0(nonprime) and 3-1/2+5/2=5(prime).

Mathematica

Select[Prime[Range[300]], Total[Boole[PrimeQ[#-1/2+{5/2, -5/2}]]]==1&] (* Harvey P. Dale, Jul 14 2019 *)

Crossrefs

Cf. A001359.

Sequence in context: A126691 A154613 A109654 * A038986 A276848 A194800

Adjacent sequences: A172067 A172068 A172069 * A172071 A172072 A172073

Keyword

nonn

Author

Juri-Stepan Gerasimov, Jan 25 2010

Extensions

Entries checked by R. J. Mathar, May 02 2010

More terms from and definition clarified by Harvey P. Dale, Jul 22 2014

Status

approved