This site is supported by donations to The OEIS Foundation.

 Please make a donation to keep the OEIS running. We are now in our 55th year. In the past year we added 12000 new sequences and reached 8000 citations (which often say "discovered thanks to the OEIS"). We need to raise money to hire someone to manage submissions, which would reduce the load on our editors and speed up editing. Other ways to donate

 Hints (Greetings from The On-Line Encyclopedia of Integer Sequences!)
 A064220 Least k such that k*11^n +/- 1 are twin primes. 0
 4, 18, 12, 12, 120, 168, 72, 78, 810, 312, 90, 138, 270, 948, 408, 192, 960, 1920, 738, 4698, 810, 1872, 6978, 2058, 3222, 570, 870, 390, 9708, 14118, 9378, 6822, 8730, 2250, 1008, 8052, 732, 5400, 2910, 5982, 2688, 16758, 1908, 258, 762, 1488, 12678 (list; graph; refs; listen; history; text; internal format)
 OFFSET 1,1 LINKS MATHEMATICA Do[ k = 1; While[ ! PrimeQ[ k*11^n + 1 ] || ! PrimeQ[ k*11^n - 1 ], k++ ]; Print[ k ], {n, 0, 50} ] lk[n_]:=Module[{c=11^n, k=1}, While[!PrimeQ[k*c+1]||!PrimeQ[k*c-1], k++]; k]; Array[lk, 50, 0] (* Harvey P. Dale, Jun 15 2019 *) CROSSREFS Cf. A063983. Sequence in context: A264003 A077109 A070923 * A205105 A231957 A275952 Adjacent sequences:  A064217 A064218 A064219 * A064221 A064222 A064223 KEYWORD nonn AUTHOR Robert G. Wilson v, Sep 21 2001 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 December 9 00:32 EST 2019. Contains 329871 sequences. (Running on oeis4.)