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Search: id:A089581
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| A089581 |
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Prime(2*n-1)*prime(2*n). |
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+0
3
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| 6, 35, 143, 323, 667, 1147, 1763, 2491, 3599, 4757, 5767, 7387, 9797, 11021, 12317, 16637, 19043, 22499, 25591, 28891, 32399, 36863, 39203, 47053, 51983, 55687, 60491, 67591, 72899, 77837, 82919, 95477, 99221, 111547, 121103, 126727, 136891
(list; graph; listen)
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OFFSET
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1,1
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COMMENT
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a(n+1) is the smallest squarefree composite number that is relatively prime to the first 2*n prime numbers.
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FORMULA
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prime(2*n-1)*prime(2*n), n=1, 2, 3 ...
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EXAMPLE
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a(13)=9797
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PROGRAM
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(PARI) p=2; q=3; i=1; a=vector(100); for(i=1, 100, a[i]=p*q; p=nextprime(q+1); p=nextprime(q+1)); a
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CROSSREFS
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Sequence in context: A101077 A094952 A024526 this_sequence A132657 A027985 A078799
Adjacent sequences: A089578 A089579 A089580 this_sequence A089582 A089583 A089584
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KEYWORD
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easy,nonn
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AUTHOR
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Norbert A'Campo (nac(AT)member.ams.org), Dec 29 2003
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EXTENSIONS
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Edited by Zak Seidov, Jun 13 2006
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