A056915 Strong pseudoprimes to bases 2, 3 and 5, i.e., intersection of A001262, A020229, and A020231.

25326001, 161304001, 960946321, 1157839381, 3215031751, 3697278427, 5764643587, 6770862367, 14386156093, 15579919981, 18459366157, 19887974881, 21276028621, 27716349961, 29118033181, 37131467521, 41752650241, 42550716781, 43536545821

Offset: 1

Author

Rick L. Shepherd, Feb 12 2002

Keywords

• nice
• nonn

Comments

These first 13 numbers are the only ones less than 25*10^9 which are simultaneously strong pseudoprimes to bases 2, 3 and 5. Taken from the same table - which indicates (only) whether they are also strong pseudoprime (spsp) or pseudoprime (psp) to base 7, 11 and/or 13: 161304001 is spsp to 11; 3215031751 is spsp to base 7 and is psp to both bases 11 and 13; 5764643587 is spsp to base 13; 14386156093 is psp to bases 7, 11 and 13. 15579919981 is psp to base 7 and spsp to base 11; 19887974881 is psp to base 7; and 21276028621 is psp to bases 11 and 13.

References

• P. Ribenboim, The Little Book of Big Primes. Springer-Verlag, NY, 1991, pp. 82-83.

Links

• Charles R Greathouse IV, Table of n, a(n) for n = 1..10000
• Pomerance, C., Selfridge, J.L. and Wagstaff, Jr., S.S. The pseudoprimes to 25*10^9, Mathematics of Computation 35, 1980, pp. 1003-1026.
• Eric Weisstein's World of Mathematics, Strong Pseudoprime
• Index entries for sequences related to pseudoprimes

Crossrefs

Cf. A072276, A001262, A020229, A020231, superset of A074773.

Extensions

B-file and more terms from Charles R Greathouse IV, Aug 14 2010