A172238 Primes p such that either p+5/2+-3/2 is prime.

2, 3, 7, 13, 19, 37, 43, 67, 79, 97, 103, 109, 127, 163, 193, 223, 229, 277, 307, 313, 349, 379, 397, 439, 457, 463, 487, 499, 613, 643, 673, 739, 757, 769, 823, 853, 859, 877, 883, 907, 937, 967, 1009, 1087, 1093, 1213, 1279, 1297, 1303, 1423, 1429, 1447, 1483

Offset

1,1

Comments

Two together with primes p such that p and p+4 are both primes.

Links

Harvey P. Dale, Table of n, a(n) for n = 1..1000

Example

a(1)=2 because 2+5/2-3/2=3(prime) and 2+5/2+3/2=6(nonprime); a(2)=3 because 3+5/2-3/2=4(nonprime) and 3+5/2+3/2=7(prime).

Mathematica

Select[Prime[Range[250]], Total[Boole[PrimeQ[#+5/2+{3/2, -3/2}]]]==1&] (* Harvey P. Dale, Jul 23 2025 *)

Crossrefs

Cf. A023200.

Sequence in context: A130272 A331948 A342529 * A319496 A038940 A019383

Adjacent sequences: A172235 A172236 A172237 * A172239 A172240 A172241

Keyword

nonn

Author

Juri-Stepan Gerasimov, Jan 29 2010

Extensions

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

Status

approved