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Search: id:A084924
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| A084924 |
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Let t(x) be the highest power of 2 which divides x+1. Then a(1)=3; a(n) is the least prime p for which t(p) > t(a(n-1)). |
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+0
1
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| 3, 7, 31, 127, 1279, 3583, 5119, 6143, 8191, 81919, 131071, 524287, 14680063, 109051903, 654311423, 738197503, 2147483647, 21474836479, 51539607551, 824633720831, 13743895347199, 26388279066623, 246290604621823
(list; graph; listen)
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OFFSET
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1,1
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LINKS
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M. F. Hasler, Table of n, a(n) for n = 1..100
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EXAMPLE
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a(5)=1279 because t(a(4))=7, and 1279 is the least prime with t(p)>7.
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PROGRAM
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(PARI) a=vector(50); a[1]=3; for(i=2, length(a), j=k=2^(factor(a[i-1]+1, 2)[1, 2]+1); while(! isprime(j-1), j+=k); a[i]=j-1); a - M. F. Hasler (maximilian.hasler(AT)gmail.com), Mar 15 2007
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CROSSREFS
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Sequence in context: A051281 A138864 A105768 this_sequence A001348 A006515 A081093
Adjacent sequences: A084921 A084922 A084923 this_sequence A084925 A084926 A084927
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KEYWORD
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nonn
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AUTHOR
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Shane Findley (TTcreation(AT)aol.com), Jul 15 2003
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EXTENSIONS
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Edited by Don Reble (djr(AT)nk.ca), May 08 2004
More terms from M. F. Hasler (maximilian.hasler(AT)gmail.com), Mar 15 2007
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