A134797 Odd isolated primes.

23, 37, 47, 53, 67, 79, 83, 89, 97, 113, 127, 131, 157, 163, 167, 173, 211, 223, 233, 251, 257, 263, 277, 293, 307, 317, 331, 337, 353, 359, 367, 373, 379, 383, 389, 397, 401, 409, 439, 443, 449, 457, 467, 479, 487, 491, 499, 503, 509, 541, 547, 557, 563, 577

Offset: 1

Author

Omar E. Pol, Nov 14 2007

Keywords

• easy
• nonn
• less

Links

• Omar E. Pol, Determinacion geometrica de los numeros primos y perfectos.

Programs

Mathematica

Flatten[Select[Split[Prime[Range[106]], #2 - #1 < 4 &], Length[#] == 1 &]] (* Jayanta Basu, Jun 07 2013 *)

PARI

select(p->!isprime(p-2)&&!isprime(p+2),primes(100)[2..100]) \\ Charles R Greathouse IV, Jun 07 2013

Formula

a(n) = A007510(n+1).

a(n) ~ n log n. - Charles R Greathouse IV, Jun 07 2013