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Search: id:A084730
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| A084730 |
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Smallest prime of the form k*n! - 1. |
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+0
2
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| 2, 3, 5, 23, 239, 719, 5039, 201599, 1088639, 14515199, 159667199, 479001599, 31135103999, 87178291199, 2615348735999, 188305108991999, 711374856191999, 192071211171839999, 3649353012264959999, 12164510040883199999
(list; graph; listen)
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OFFSET
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2,1
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EXAMPLE
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a(8) = 161599 = 4*8! - 1 is a prime.
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MATHEMATICA
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Do[k = 1; While[ !PrimeQ[k*n! - 1], k++ ]; Print[k*n! - 1], {n, 2, 20}]
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PROGRAM
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(PARI) a(n)=if(n<1, 0, k=1; while(isprime(k*n!-1)==0, k++); k*n!-1)
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CROSSREFS
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Cf. A083663.
Sequence in context: A138655 A053708 A137070 this_sequence A117696 A024774 A068543
Adjacent sequences: A084727 A084728 A084729 this_sequence A084731 A084732 A084733
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KEYWORD
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nonn
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AUTHOR
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Amarnath Murthy and Meenakshi Srikanth (amarnath_murthy(AT)yahoo.com), Jun 13 2003
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EXTENSIONS
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Corrected and extended by Benoit Cloitre (benoit7848c(AT)orange.fr), Jun 14 2003
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