cp's OEIS Frontend

This is a front-end for the Online Encyclopedia of Integer Sequences, made by Christian Perfect. The idea is to provide OEIS entries in non-ancient HTML, and then to think about how they're presented visually. The source code is on GitHub.

A358381 Primes p such that q1=6*p-1 and q2=6*p+1 are also primes (twin primes) and q1 is a Sophie Germain prime (i.e., 2*q1+1 is prime).

Original entry on oeis.org

2, 5, 7, 47, 107, 907, 2137, 2347, 3407, 4547, 4597, 8377, 9067, 9277, 9767, 14537, 16427, 18307, 19507, 19997, 23447, 23917, 26927, 27437, 28837, 29297, 33037, 37307, 38327, 45127, 46457, 50957, 52957, 55897, 59077, 59407, 60317, 63667, 65497, 69767, 74377, 77527, 86587, 86837
Offset: 1

Views

Author

Tamas Nagy, Nov 12 2022

Keywords

Comments

Except for the first 2 terms, every term's last digit is a 7 in base 10.

Crossrefs

Subsequence of A060212.
Cf. A005384.

Programs

  • Maple
    filter:= p -> andmap(isprime, [p, 6*p-1, 6*p+1, 12*p-1]):
    select(filter, [2,5,seq(i,i=7..10^5,10)]); # Robert Israel, Dec 23 2022
  • Mathematica
    Select[Prime[Range[8500]], PrimeQ[6*# - 1] && PrimeQ[6*# + 1] && PrimeQ[12*# - 1] &] (* Amiram Eldar, Nov 13 2022 *)