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A115395 Primes p such that p+/-6 are semiprimes. 3
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 (list; graph; refs; listen; history; text; internal format)
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

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Last modified September 20 08:10 EDT 2021. Contains 347577 sequences. (Running on oeis4.)