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A147667
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Primes of the form 5^n - 4^n.
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2
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61, 1136791005963704961126617632861, 173472015290681763212224222187425603741981, 31861838222649045530727106406255616308752331078816472270207782250106896363274089867800367051529351065966102374800998198276889145001421
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OFFSET
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1,1
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COMMENTS
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All terms are odd, and if n is even, then 5^n - 4^n is divisible by 3. [Vincenzo Librandi, Nov 25 2010]
The next term (a(5)) has 156 digits. - Harvey P. Dale, May 14 2022
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LINKS
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Muniru A Asiru, Table of n, a(n) for n = 1..9
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EXAMPLE
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5^3 - 4^3 = 125 - 64 = 61.
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MAPLE
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select(isprime, [seq(5^n - 4^n, n=0..200)]); # Muniru A Asiru, Mar 04 2018
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MATHEMATICA
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lst={}; Do[p=5^n-4^n; If[PrimeQ[p], AppendTo[lst, p]], {n, 6!}]; lst
Select[Table[5^n-4^n, {n, 300}], PrimeQ] (* Harvey P. Dale, May 14 2022 *)
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PROG
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(GAP) Filtered(List([1..200], n->5^n - 4^n), IsPrime); # Muniru A Asiru, Mar 04 2018
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CROSSREFS
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Cf. A059802 (corresponding n).
Sequence in context: A087513 A176272 A173418 * A022084 A110823 A058913
Adjacent sequences: A147664 A147665 A147666 * A147668 A147669 A147670
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KEYWORD
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nonn,changed
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AUTHOR
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Vladimir Joseph Stephan Orlovsky, Nov 10 2008
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STATUS
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approved
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