A129621 Primes p such that at least one of k-1 and k+1 is prime, where k = sum of the two neighboring primes of 3*p.

2, 3, 5, 7, 11, 13, 17, 19, 23, 29, 37, 41, 43, 59, 61, 67, 71, 73, 83, 97, 101, 103, 107, 109, 113, 127, 131, 137, 139, 151, 157, 163, 173, 179, 181, 193, 197, 199, 227, 229, 239, 241, 257, 263, 269, 277, 281, 283, 293, 307, 311, 313, 317, 331, 347, 349, 353

Offset

1,1

Links

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

Example

29*3 = 87, neighboring primes are 83 and 89 which sum to 172; 173 is prime, hence 29 is in the sequence.
31*3 = 93, neighboring primes are 89 and 97 which sum to 186; neither 185 nor 187 is prime, hence 31 is not in the sequence.
1091*3 = 3273, neighboring primes are 3271 and 3299 which sum to 6570; both 6569 and 6571 are prime, hence 1091 is in the sequence.

Prog

(PARI) {m=360; forprime(p=2, m, d=3*p; k=precprime(d)+nextprime(d); if(isprime(k-1)||isprime(k+1), print1(p, ", ")))} /* Klaus Brockhaus, Jun 05 2007 */

Crossrefs

Cf. A127566.

Sequence in context: A233393 A233265 A095319 * A316504 A077500 A036955

Adjacent sequences: A129618 A129619 A129620 * A129622 A129623 A129624

Keyword

nonn

Author

J. M. Bergot, May 30 2007

Extensions

Edited and extended by Klaus Brockhaus, Jun 05 2007

Status

approved