OFFSET
1,1
LINKS
Amiram Eldar, Table of n, a(n) for n = 1..165 (terms below 10^11; terms 1..84 from Robert G. Wilson v)
Eric Weisstein's World of Mathematics, Fermat Pseudoprime.
MATHEMATICA
Do[ f=PowerMod[ 11, 2n-1, 2n ]; If[ f==1, Print[ 2n ] ], {n, 2, 800000} ] (* Alexander Adamchuk, May 26 2007 *)
lst = {}; Do[ If[ PowerMod[11, 2n - 1, 2n] == 1, AppendTo[lst, 2n]], {n, 2, 2*10^9}]; lst (* Robert G. Wilson v, Jun 01 2007 *)
Select[Range[4, 68926000, 2], PowerMod[11, #-1, #]==1&] (* Harvey P. Dale, Oct 16 2021 *)
PROG
(PARI) is(k) = k > 2 && !(k % 2) && Mod(11, k)^(k-1) == 1; \\ Amiram Eldar, Sep 18 2024
CROSSREFS
KEYWORD
nonn
AUTHOR
Labos Elemer, Nov 25 2003
EXTENSIONS
More terms from Alexander Adamchuk, May 26 2007
Further terms from Robert G. Wilson v, Jun 01 2007
STATUS
approved