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Search: id:A135725
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| A135725 |
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Positive integers n such that n!!!-1 = A007661(n)-1 is prime. |
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+0
2
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| 3, 4, 6, 8, 20, 26, 36, 50, 60, 114, 135, 138, 248, 315, 351, 429, 642
(list; graph; listen)
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OFFSET
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1,1
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LINKS
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Ken Davis, Status of Search for Multifactorial Primes
ProthSearch.net (on web.archive.org), n3minus.txt
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EXAMPLE
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a(4)=8 since 8!!!-1 = 8x5x2-1 = 79 is the 4th prime of that form.
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PROGRAM
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(PARI) A007661(n) = prod(i=1, (n-1)\3, n-=3, n+!n) /* newline */ for(n=1, 999, if(isprime(A007661(n)-1), print1(n", ")))
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CROSSREFS
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Cf. A007661, A135726, A037082, A037083.
Sequence in context: A007749 A139452 A063506 this_sequence A084438 A080710 A115837
Adjacent sequences: A135722 A135723 A135724 this_sequence A135726 A135727 A135728
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KEYWORD
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hard,more,nonn
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AUTHOR
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M. F. Hasler (Maximilian.Hasler(AT)gmail.com), Nov 26 2007
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