A064220 Least k such that k*11^n +/- 1 are twin primes.

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

Offset

0,1

Links

Table of n, a(n) for n=0..46.

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, A064213, A064214, A064215. A064217, A064218, A064221.

Sequence in context: A264003 A077109 A070923 * A205105 A371414 A231957

Adjacent sequences: A064217 A064218 A064219 * A064221 A064222 A064223

Keyword

nonn

Author

Robert G. Wilson v, Sep 21 2001

Extensions

Offset corrected by Georg Fischer, May 01 2022

Status

approved