A090084 Even pseudoprimes to base 11.

10, 70, 190, 1330, 8170, 9730, 24130, 28462, 58030, 98458, 143830, 144886, 327370, 856786, 1580230, 1620130, 3536470, 5274970, 6082490, 6376126, 6792710, 8066170, 8610610, 14076910, 17728930, 27275158, 42447406, 52970386, 53497978, 68925130

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.

Index entries for sequences related to pseudoprimes.

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

Cf. A020139.

Cf. A006935, A130433, A090082, A090083, A090085, A130434, A130435, A130436, A130438, A130439, A130440, A130441, A130442, A130443.

Sequence in context: A320228 A130548 A160662 * A025221 A271040 A005567

Adjacent sequences: A090081 A090082 A090083 * A090085 A090086 A090087

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