login

Year-end appeal: Please make a donation to the OEIS Foundation to support ongoing development and maintenance of the OEIS. We are now in our 61st year, we have over 378,000 sequences, and we’ve reached 11,000 citations (which often say “discovered thanks to the OEIS”).

A129310
Numbers k such that 6*p(k)*p(k+1)*p(k+2)*p(k+3)*p(k+4)-1 and 6*p(k)*p(k+1)*p(k+2)*p(k+3)*p(k+4)+1 are twin primes with p(h) = h-th prime.
3
4, 38, 120, 122, 569, 795, 1250, 1310, 1826, 3276, 3610, 4838, 4870, 4931, 4982, 5440, 5477, 5821, 6582, 6821, 6872, 7644, 7875, 8475, 9066, 9636, 9733, 10013, 10960, 11171, 12079, 13887, 14338, 15669, 15952, 16040, 17597, 18921, 19525, 19694, 21321, 21372, 22750, 25998
OFFSET
1,1
LINKS
MATHEMATICA
PrimePi[Part[#, 1, 1] & /@ FactorInteger /@ Select[Times @@@ Partition[Prime[Range[3*10^4]], 5, 1], PrimeQ[6 # + 1] && PrimeQ[6 # - 1] &]] (* Amiram Eldar, Jan 26 2020 after Giovanni Resta at A129311 *)
PROG
(PARI) isok(k) = isprime(p=6*prime(k)*prime(k+1)*prime(k+2)*prime(k+3)*prime(k+4)-1) && isprime(p+2); \\ Michel Marcus, Sep 24 2019
CROSSREFS
Sequence in context: A020205 A265437 A003633 * A152110 A209486 A245129
KEYWORD
nonn
AUTHOR
Pierre CAMI, Apr 09 2007
EXTENSIONS
More terms from Michel Marcus, Sep 24 2019
STATUS
approved