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A090082
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Even pseudoprimes to base 5.
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15
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4, 124, 5662, 11476, 59356, 80476, 91636, 250876, 261964, 482516, 1385836, 1892458, 1926676, 2428084, 2589796, 3743476, 4101796, 6797764, 9155476, 10701076, 10743436, 11263396, 13799836, 13859956, 15570556, 20396476
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OFFSET
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1,1
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LINKS
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Charles R Greathouse IV, Table of n, a(n) for n = 1..100
Index entries for sequences related to pseudoprimes
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MATHEMATICA
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Do[s=Mod[ -1+5^(n-1), n]; If[Equal[s, 0]&&!PrimeQ[n]&&EvenQ[n], Print[n]], {n, 1, 1000000}]
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PROG
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(PARI) is(n)=Mod(5, n)^(n-1)==1&&!isprime(n)&&n%2==0 \\ Charles R Greathouse IV, Apr 12 2012
(PARI) p=2; forprime(q=3, 1e8, forstep(n=p+1, q-1, 2, if(Mod(5, n)^(n-1)==1, print1(n", "))); p=q) \\ Charles R Greathouse IV, Apr 12 2012
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CROSSREFS
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Cf. A005936.
Sequence in context: A241648 A197779 A197610 * A243010 A343427 A209040
Adjacent sequences: A090079 A090080 A090081 * A090083 A090084 A090085
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KEYWORD
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nonn
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AUTHOR
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Labos Elemer, Nov 25 2003
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EXTENSIONS
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More terms from Farideh Firoozbakht, Sep 13 2006
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STATUS
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approved
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