A114247 Number of Fermat pseudoprimes to base 5 less than 10^n.
1, 1, 5, 20, 73, 248, 745, 1954, 5239, 13837, 36042, 92893
Offset: 1
Links
- Eric Weisstein's World of Mathematics, Fermat Pseudoprime
- Index entries for sequences related to pseudoprimes
Programs
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Mathematica
Table[Count[Select[Range[2, 10^6], ! PrimeQ[#] && PowerMod[5, # - 1, #] == 1 &], x_ /; x < 10^n], {n, 6}] (* Robert Price, Jun 09 2019 *)
Extensions
a(9)-a(12) from Hiroaki Yamanouchi, Sep 25 2015