A114248 - OEIS

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A114248

Number of Fermat pseudoprimes to bases 2, 3 and 5 less than 10^n.

0, 0, 0, 4, 11, 36, 95, 257, 685, 1747, 4405, 10601, 25991, 63589, 156965, 387971, 973753, 2471133, 6340799

(list; graph; refs; listen; history; text; internal format)

OFFSET

1,4

LINKS

Table of n, a(n) for n=1..19.

Eric Weisstein's World of Mathematics, Fermat Pseudoprime.

Index entries for sequences related to pseudoprimes.

MATHEMATICA

Table[Count[Select[Range[2, 10^6], ! PrimeQ[#] && PowerMod[2, # - 1, #] == 1 && PowerMod[3, # - 1, #] == 1 && PowerMod[5, # - 1, #] == 1 &], x_ /; x < 10^n], {n, 6}] (* Robert Price, Jun 09 2019 *)

CROSSREFS

Cf. A083737.

Sequence in context: A358826 A212910 A339034 * A149237 A054577 A206687

Adjacent sequences: A114245 A114246 A114247 * A114249 A114250 A114251

KEYWORD

nonn,more

AUTHOR

Eric W. Weisstein, Nov 18 2005

EXTENSIONS

a(9)-a(19) from Amiram Eldar, Apr 16 2022

STATUS

approved