The OEIS Foundation is supported by donations from users of the OEIS and by a grant from the Simons Foundation.

 Hints (Greetings from The On-Line Encyclopedia of Integer Sequences!)
 A225057 Least prime p such that p*6^n +/- 1 are primes. 0
 2, 2, 2, 2, 47, 3, 53, 677, 823, 227, 1907, 1103, 17, 163, 2693, 1213, 277, 2767, 887, 8353, 1013, 773, 6967, 1423, 2593, 9643, 157, 18013, 263, 2137, 2837, 107, 3467, 2137, 17, 2777, 1453, 2683, 7963, 3517, 2767, 53527, 8563, 227, 367, 27673, 30853, 5087, 7723, 14753, 41687, 137, 48647, 26357, 16747, 2797, 9887, 35933 (list; graph; refs; listen; history; text; internal format)
 OFFSET 1,1 COMMENTS a(1) >= A064215(n). First n's such that a(n) = A064215(n): 2, 3, 4, 6, 13, 27, 29, 32, 35, 40, 44, 45, 52, 60, 67, 71, 79, 86, 87, 97, 99. According to Dickson's Conjecture a(n) exists for any n. LINKS Chris Caldwell, Prime Glossary: Dickson's Conjecture MATHEMATICA Table[ n6=6^n; p = 2; While[ ! PrimeQ[q = p*n6 + 1 ] || ! PrimeQ[ q - 2 ], p = NextPrime[p] ]; p, {n, 100}] CROSSREFS Cf. A064215 (least k: k*6^n +/- 1 are  primes). Sequence in context: A320017 A289087 A154288 * A084954 A226281 A217993 Adjacent sequences:  A225054 A225055 A225056 * A225058 A225059 A225060 KEYWORD nonn AUTHOR Zak Seidov, Apr 26 2013 STATUS approved

Lookup | Welcome | Wiki | Register | Music | Plot 2 | Demos | Index | Browse | More | WebCam
Contribute new seq. or comment | Format | Style Sheet | Transforms | Superseeker | Recent
The OEIS Community | Maintained by The OEIS Foundation Inc.

Last modified June 23 18:45 EDT 2021. Contains 345402 sequences. (Running on oeis4.)