A130433 Even pseudoprimes to base 3.

286, 24046, 232726, 1304446, 1707266, 2232026, 3197806, 3922126, 4446982, 5603326, 5886166, 10123366, 10169926, 12304774, 13658086, 45133726, 47766286, 52249654, 62656126, 75421126, 76254046, 91459126, 91612246, 96956926, 108571606, 139868326, 151513846

Offset: 1

Author

Alexander Adamchuk, May 26 2007, Jun 17 2007

Keywords

• nonn

Comments

The first 27 terms (halved) are given in Table 1 by Paszkiewicz and Rotkiewicz. - R. J. Mathar, Aug 22 2012

Links

• Amiram Eldar, Table of n, a(n) for n = 1..215 (terms below 10^12, calculated from the b-file at A005935; terms 1..68 from Jeppe Stig Nielsen)
• Adam Paszkiewicz and Andrzej Rotkiewicz, On a Problem of H. J. A. Duprac, Tatra Mt. Math. Publ. 32 (2005) 15-32, MR2206908.
• Eric Weisstein's World of Mathematics, Fermat Pseudoprime.
• Index entries for sequences related to pseudoprimes.

Crossrefs

Even terms of A005935.

Terms of A122780 that are congruent to 2 or 4 modulo 6.

Cf. A006935, A090082, A090083, A090084, A090085.

Cf. A130434, A130435, A130436, A130437, A130438, A130439, A130440, A130441, A130442, A130443.

Programs

Mathematica

Do[ f=PowerMod[ 3, 2n-1, 2n ]; If[ f==1, Print[ 2n ] ], {n,2,7000000} ]

PARI

forstep(n=4,10^10,2,Mod(3,n)^(n-1)==1 && print1(n,", ")) \\ Jeppe Stig Nielsen, Apr 25 2018

Extensions

More terms from Alexander Adamchuk, Jun 17 2007

a(25)-a(27) from Jeppe Stig Nielsen, Apr 25 2018