A114249 Number of Fermat pseudoprimes to base 7 less than 10^n.

1, 2, 6, 16, 73, 234, 659, 1797, 4950, 13070, 33989, 87448

Offset: 1

Author

Eric W. Weisstein, Nov 18 2005

Keywords

• nonn
• more

Links

• Eric Weisstein's World of Mathematics, Fermat Pseudoprime

Crossrefs

Cf. A005938, A055550, A114245, A114247.

Programs

Mathematica

Table[Count[Select[Range[2, 10^6], ! PrimeQ[#] && PowerMod[7, # - 1, #] == 1 &], x_ /; x < 10^n], {n, 6}]  (* Robert Price, Jun 09 2019 *)

Extensions

a(9)-a(12) from Hiroaki Yamanouchi, Sep 25 2015