A115395 Primes p such that p+/-6 are semiprimes.

71, 127, 139, 149, 211, 241, 293, 397, 401, 409, 421, 479, 487, 491, 499, 521, 523, 617, 661, 673, 691, 701, 743, 761, 773, 787, 797, 809, 907, 911, 967, 1049, 1061, 1151, 1153, 1163, 1171, 1201, 1213, 1249, 1279, 1399, 1409, 1471, 1523, 1571, 1583, 1597

Offset

1,1

Links

K. D. Bajpai, Table of n, a(n) for n = 1..10000

Example

71-6=65=5*13 (semiprime), 71+6=77=7*11 (semiprime).

Mathematica

A115395 = {}; k = Prime[n]; Do[If[PrimeOmega[k + 6] == 2 && PrimeOmega[k - 6] == 2, AppendTo[A115395, k]], {n, 1000}]; A115395  (* K. D. Bajpai, Jun 24 2014 *)

Prog

(PARI) lista(nn) = {pr = primes(nn); pp = select(i->((bigomega(i-6) == 2) && (bigomega(i+6) == 2)), pr); print(pp); } \\ Michel Marcus, Oct 09 2013

Crossrefs

Cf. A063643 Primes p such that p+/-2 are semiprimes, A117328 Primes p such that p+/-4 are semiprimes.

Sequence in context: A323049 A026063 A244167 * A142647 A152951 A090799

Adjacent sequences: A115392 A115393 A115394 * A115396 A115397 A115398

Keyword

nonn

Author

Zak Seidov, Mar 08 2006

Status

approved