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Search: id:A139758
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| A139758 |
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a(n) is the smallest prime such that (a(n) - the nth prime) is a power of 2. |
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+0
1
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| 3, 5, 7, 11, 13, 17, 19, 23, 31, 31, 47, 41, 43, 47, 79, 61, 61, 317, 71, 73, 89, 83, 211, 97, 101, 103, 107, 109, 113, 241, 131, 139, 139, 1163, 151, 167, 173, 167, 199, 181, 181, 197, 193, 197, 199, 263, 227, 227, 229, 233, 241, 241, 257, 283, 769, 271, 271
(list; graph; listen)
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OFFSET
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1,1
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COMMENT
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It is only conjectured (see Cino Hilliard's comment at A094076) that this sequence is defined for all n.
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FORMULA
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a(n)=A000040(n)+2^A094076(n). - R. J. Mathar (mathar(AT)strw.leidenuniv.nl), May 20 2008
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MAPLE
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A094076 := proc(n) local k, p ; k := 0 ; p := ithprime(n) ; while not isprime(p+2^k) do k := k+1 ; od: k ; end: A139758 := proc(n) ithprime(n)+2^A094076(n) ; end: seq(A139758(n), n=1..80) ; - R. J. Mathar (mathar(AT)strw.leidenuniv.nl), May 20 2008
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CROSSREFS
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Cf. A094076, A033875.
Adjacent sequences: A139755 A139756 A139757 this_sequence A139759 A139760 A139761
Sequence in context: A130057 A120637 A064534 this_sequence A060770 A120334 A000978
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KEYWORD
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nonn
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AUTHOR
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Leroy Quet (qq-quet(AT)mindspring.com), May 19 2008
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EXTENSIONS
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More terms from R. J. Mathar (mathar(AT)strw.leidenuniv.nl), May 20 2008
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