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Search: id:A033997
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| A033997 |
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Numbers n such that sum of first n primes is a square. |
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+0
4
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OFFSET
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1,1
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LINKS
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G. L. Honaker Jr. and C. Caldwell, Prime Curios!: 9
C. Riveras, PrimePuzzles.Net, Problem 9: Sum of first k primes is perfect square
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FORMULA
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a(n) = PrimePi(A033998(n))
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EXAMPLE
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Sum of first 9 primes is 2+3+5+7+11+13+17+19+23 = 100, which is square, so 9 is in the sequence.
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CROSSREFS
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Cf. A000040, A033998, A061888, A061890.
Sequence in context: A013827 A058428 A069704 this_sequence A068729 A046896 A036516
Adjacent sequences: A033994 A033995 A033996 this_sequence A033998 A033999 A034000
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KEYWORD
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nonn
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AUTHOR
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Calculated by Jud McCranie (j.mccranie(AT)comcast.net)
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EXTENSIONS
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126789311423 from Giovanni Resta (g.resta(AT)iit.cnr.it), May 27 2003
Edited by Ray Chandler (rayjchandler(AT)sbcglobal.net), Mar 20 2007
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