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A160709 Centuries containing a prime number of primes. +0
1
5, 14, 15, 20, 26, 30, 33, 35, 37, 39, 40, 45, 52, 55, 56, 60, 62, 63, 66, 70, 73, 75, 81, 87, 88, 89, 91, 93, 94, 96, 97, 98, 101, 108, 112, 115, 120, 122, 125, 131, 135, 140, 143, 155, 157, 166, 167, 168, 171, 175, 182, 183, 184, 185, 188, 189, 191, 192, 193, 196 (list; graph; listen)
OFFSET

1,1

LINKS

H. v. Eitzen, Table of n, a(n) for n=1..10000

FORMULA

{n: A157765(n) is in A000040}.

EXAMPLE

a(1) = 5 because 5 is the first Century to have a prime number (17) of primes.

MAPLE

A157765 := proc(n) numtheory[pi](n*100)-numtheory[pi]((n-1)*100) ; end: A160709 := proc(n) option remember ; local a; if n = 1 then 5 ; else for a from procname(n-1)+1 do if isprime( A157765(a) ) then RETURN(a) ; fi; od: fi; end: seq(A160709(n), n=1...90) ; [From R. J. Mathar (mathar(AT)strw.leidenuniv.nl), May 27 2009]

CROSSREFS

Cf. A000040, A157765.

Sequence in context: A051542 A083660 A003079 this_sequence A067113 A101774 A053782

Adjacent sequences: A160706 A160707 A160708 this_sequence A160710 A160711 A160712

KEYWORD

easy,nonn

AUTHOR

Jonathan Vos Post (jvospost3(AT)gmail.com), May 25 2009

EXTENSIONS

Extended by Ray Chandler (rayjchandler(AT)sbcglobal.net), May 25 2009

More terms from R. J. Mathar (mathar(AT)strw.leidenuniv.nl), May 27 2009

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Last modified December 7 08:40 EST 2009. Contains 170430 sequences.


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