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

%I A056915 #19 Feb 16 2025 08:32:43
%S A056915 25326001,161304001,960946321,1157839381,3215031751,3697278427,
%T A056915 5764643587,6770862367,14386156093,15579919981,18459366157,
%U A056915 19887974881,21276028621,27716349961,29118033181,37131467521,41752650241,42550716781,43536545821
%N A056915 Strong pseudoprimes to bases 2, 3 and 5, i.e., intersection of A001262, A020229, and A020231.
%C A056915 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.
%D A056915 P. Ribenboim, The Little Book of Big Primes. Springer-Verlag, NY, 1991, pp. 82-83.
%H A056915 Charles R Greathouse IV, <a href="/A056915/b056915.txt">Table of n, a(n) for n = 1..10000</a>
%H A056915 Pomerance, C., Selfridge, J.L. and Wagstaff, Jr., S.S. <a href="http://dx.doi.org/10.1090/S0025-5718-1980-0572872-7">The pseudoprimes to 25*10^9</a>, Mathematics of Computation 35, 1980, pp. 1003-1026.
%H A056915 Eric Weisstein's World of Mathematics, <a href="https://mathworld.wolfram.com/StrongPseudoprime.html">Strong Pseudoprime</a>
%H A056915 <a href="/index/Ps#pseudoprimes">Index entries for sequences related to pseudoprimes</a>
%Y A056915 Cf. A072276, A001262, A020229, A020231, superset of A074773.
%K A056915 nice,nonn
%O A056915 1,1
%A A056915 _Rick L. Shepherd_, Feb 12 2002
%E A056915 B-file and more terms from _Charles R Greathouse IV_, Aug 14 2010