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Search: id:A075557
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| A075557 |
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a(n) is the smallest odd prime such that (1) a(n) doesn't already appear in the sequence; (2) the n-th partial sum is divisible by n; and (3) the n-th partial sum is relatively prime to n+1. |
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+0
2
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| 3, 5, 7, 13, 37, 31, 23, 17, 53, 11, 251, 29, 79, 43, 73, 61, 97, 67, 107, 173, 59, 103, 199, 163, 7, 1, 149, 47, 101, 509, 89, 151, 283, 229, 271, 211, 109, 257, 113, 269, 157, 241, 331, 83, 389, 41, 313, 1543, 19, 307, 463, 373, 277, 811, 457, 137, 191, 419, 311, 197
(list; graph; listen)
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OFFSET
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1,1
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COMMENT
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Condition (3) is needed to ensure that a(n+1) exists.
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EXAMPLE
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a(5)=37: The 4th partial sum is 28. 7 is the smallest odd prime that satisfies (2) (28+7=35), but 7 has already been used. 17 satisfies (1) and (2) (28+17=45), but 45+a(6) must be a multiple of 6, and the only odd prime satisfying that requirement is 3, which has already been used. 37 works (28+37=65).
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CROSSREFS
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Sequence in context: A038928 A089740 A047933 this_sequence A057187 A064268 A118743
Adjacent sequences: A075554 A075555 A075556 this_sequence A075558 A075559 A075560
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KEYWORD
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nonn,easy
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AUTHOR
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Amarnath Murthy (amarnath_murthy(AT)yahoo.com), Sep 24 2002
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EXTENSIONS
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Edited by David Wasserman (wasserma(AT)spawar.navy.mil), Jun 27 2003
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