A129310 - 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.

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

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OFFSET

1,1

LINKS

Amiram Eldar, Table of n, a(n) for n = 1..10000

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

Cf. A129311, A129313.

Sequence in context: A020205 A265437 A003633 * A152110 A209486 A245129

Adjacent sequences: A129307 A129308 A129309 * A129311 A129312 A129313

KEYWORD

nonn

AUTHOR

Pierre CAMI, Apr 09 2007

EXTENSIONS

More terms from Michel Marcus, Sep 24 2019

STATUS

approved