login
The OEIS Foundation is supported by donations from users of the OEIS and by a grant from the Simons Foundation.

 

Logo


Hints
(Greetings from The On-Line Encyclopedia of Integer Sequences!)
A020306 Strong pseudoprimes to base 80. 1

%I

%S 9,27,49,81,169,301,481,2107,3439,5461,6253,6401,7107,8261,10349,

%T 16609,18361,23281,25351,29089,46531,49051,55231,58969,75851,79501,

%U 113401,115231,117569,119341,123139,138881,146611,157753,158701,188501,200911

%N Strong pseudoprimes to base 80.

%H R. J. Mathar, <a href="/A020306/b020306.txt">Table of n, a(n) for n = 1..300</a>

%H <a href="/index/Ps#pseudoprimes">Index entries for sequences related to pseudoprimes</a>

%t strongPseudoprimeQ[b_, n_] := Module[{rems = Table[PowerMod[b, (n - 1)/2^expo, n], {expo, 0, IntegerExponent[n - 1, 2]}]}, (rems[[-1]] == 1 || MemberQ[rems, n - 1]) && PowerMod[b, n - 1, n] == 1]; max = 5000; Select[Complement[Range[2, max], Prime[Range[PrimePi[max]]]], strongPseudoprimeQ[80, #] &] (* _Alonso del Arte_, Aug 10 2018 *)

%K nonn

%O 1,1

%A _David W. Wilson_

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.

License Agreements, Terms of Use, Privacy Policy. .

Last modified July 15 23:32 EDT 2020. Contains 335774 sequences. (Running on oeis4.)