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A139758 a(n) is the smallest prime such that (a(n) - the nth prime) is a power of 2. +0
2
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)
OFFSET

1,1

COMMENT

It is only conjectured (see Cino Hilliard's comment at A094076) that this sequence is defined for all n.

LINKS

Leroy Quet, Home Page (listed in lieu of email address)

FORMULA

a(n)=A000040(n)+2^A094076(n). - R. J. Mathar (mathar(AT)strw.leidenuniv.nl), May 20 2008

MAPLE

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

CROSSREFS

Cf. A094076, A033875.

Sequence in context: A130057 A120637 A064534 this_sequence A060770 A120334 A000978

Adjacent sequences: A139755 A139756 A139757 this_sequence A139759 A139760 A139761

KEYWORD

nonn

AUTHOR

Leroy Quet May 19 2008

EXTENSIONS

More terms from R. J. Mathar (mathar(AT)strw.leidenuniv.nl), May 20 2008

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Last modified December 11 12:57 EST 2009. Contains 170656 sequences.


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