A052155 Pseudoprimes to both base 2 and base 3, i.e., intersection of A001567 and A005935.

1105, 1729, 2465, 2701, 2821, 6601, 8911, 10585, 15841, 18721, 29341, 31621, 41041, 46657, 49141, 52633, 63973, 75361, 83333, 83665, 88561, 90751, 93961, 101101, 104653, 107185, 115921, 126217, 162401, 172081, 176149, 188461

Offset: 1

Author

Harvey P. Dale, Jan 24 2000

Keywords

• nice
• nonn

Links

• Charles R Greathouse IV, Table of n, a(n) for n = 1..10000 (first 201 terms from R. J. Mathar)
• J. Bernheiden, Pseudoprimes (Text in German)
• Index entries for sequences related to pseudoprimes

Crossrefs

Cf. A001567, A005935, A083737.

Programs

Mathematica

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

PARI

is(n)=!isprime(n)&&Mod(2,n)^(n-1)==1&&Mod(3,n)^(n-1)==1 \\ Charles R Greathouse IV, Apr 12 2012