A052155 - OEIS

%I #13 Nov 29 2017 11:47:31

%S 1105,1729,2465,2701,2821,6601,8911,10585,15841,18721,29341,31621,

%T 41041,46657,49141,52633,63973,75361,83333,83665,88561,90751,93961,

%U 101101,104653,107185,115921,126217,162401,172081,176149,188461

%N Pseudoprimes to both base 2 and base 3, i.e., intersection of A001567 and A005935.

%H Charles R Greathouse IV, <a href="/A052155/b052155.txt">Table of n, a(n) for n = 1..10000</a> (first 201 terms from R. J. Mathar)

%H J. Bernheiden, <a href="http://www.mathe-schule.de/download/pdf/Primzahl/PSP.pdf">Pseudoprimes (Text in German)</a>

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

%t Select[ Range[228240], !PrimeQ[ # ] && PowerMod[2, # - 1, # ] == 1 && PowerMod[3, # - 1, # ] == 1 &]

%o (PARI) is(n)=!isprime(n)&&Mod(2,n)^(n-1)==1&&Mod(3,n)^(n-1)==1 \\ _Charles R Greathouse IV_, Apr 12 2012

%Y Cf. A001567, A005935, A083737.

%K nice,nonn

%O 1,1

%A _Harvey P. Dale_, Jan 24 2000