The OEIS is supported by the many generous donors to the OEIS Foundation.

 Hints (Greetings from The On-Line Encyclopedia of Integer Sequences!)
 A243158 Smallest k>=0 such that prime(n)*prime(n+k) + 2 is prime. 3
 0, 1, 1, 3, 1, 5, 1, 3, 4, 4, 3, 5, 2, 6, 13, 5, 6, 1, 9, 28, 8, 2, 10, 8, 5, 8, 3, 3, 31, 2, 2, 9, 6, 1, 3, 6, 2, 5, 4, 1, 10, 3, 7, 3, 6, 7, 4, 4, 1, 14, 1, 1, 4, 4, 18, 1, 8, 1, 3, 10, 3, 1, 6, 1, 7, 2, 26, 19, 6, 2, 8, 30, 23, 6, 19, 5, 1, 1, 12, 1, 7 (list; graph; refs; listen; history; text; internal format)
 OFFSET 2,4 COMMENTS A dual sequence to A243154. The sequence contains a unique zero term. Indeed, every prime p>3 has the form 3*k +/- 1. So, p^2 + 2 == 0 (mod 3). LINKS Table of n, a(n) for n=2..82. MATHEMATICA skp[n_]:=Module[{c=Prime[n], k=0}, While[!PrimeQ[c*Prime[n+k]+2], k++]; k]; Array[ skp, 90, 2] (* Harvey P. Dale, May 08 2021 *) PROG (PARI) vector(200, n, k=0; while(!isprime(prime(n+1)*prime(n+1+k)+2), k++); k) \\ Colin Barker, May 31 2014 CROSSREFS Cf. A243154. Sequence in context: A016475 A037227 A056753 * A154723 A273262 A274532 Adjacent sequences: A243155 A243156 A243157 * A243159 A243160 A243161 KEYWORD nonn AUTHOR Vladimir Shevelev, May 31 2014 EXTENSIONS More terms from Colin Barker, May 31 2014 STATUS approved

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

Last modified August 4 17:04 EDT 2024. Contains 374923 sequences. (Running on oeis4.)