# Greetings from The On-Line Encyclopedia of Integer Sequences! http://oeis.org/ Search: id:a129310 Showing 1-1 of 1 %I A129310 #16 Jan 26 2020 11:05:56 %S A129310 4,38,120,122,569,795,1250,1310,1826,3276,3610,4838,4870,4931,4982, %T A129310 5440,5477,5821,6582,6821,6872,7644,7875,8475,9066,9636,9733,10013, %U A129310 10960,11171,12079,13887,14338,15669,15952,16040,17597,18921,19525,19694,21321,21372,22750,25998 %N 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. %H A129310 Amiram Eldar, Table of n, a(n) for n = 1..10000 %t A129310 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 *) %o A129310 (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 %Y A129310 Cf. A129311, A129313. %K A129310 nonn %O A129310 1,1 %A A129310 _Pierre CAMI_, Apr 09 2007 %E A129310 More terms from _Michel Marcus_, Sep 24 2019 # Content is available under The OEIS End-User License Agreement: http://oeis.org/LICENSE