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Search: id:A057820
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| A057820 |
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First differences of sequence of consecutive prime powers (A000961). |
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+0
8
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| 1, 1, 1, 1, 2, 1, 1, 2, 2, 3, 1, 2, 4, 2, 2, 2, 2, 1, 5, 4, 2, 4, 2, 4, 6, 2, 3, 3, 4, 2, 6, 2, 2, 6, 8, 4, 2, 4, 2, 4, 8, 4, 2, 1, 3, 6, 2, 10, 2, 6, 6, 4, 2, 4, 6, 2, 10, 2, 4, 2, 12, 12, 4, 2, 4, 6, 2, 2, 8, 5, 1, 6, 6, 2, 6, 4, 2, 6, 4, 14, 4, 2, 4, 14, 6, 6, 4, 2, 4, 6, 2, 6, 6, 6, 4, 6, 8, 4, 8, 10, 2, 10
(list; graph; listen)
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OFFSET
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0,5
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COMMENT
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a(n) = 1 iff A000961(n) = A006549(k) for some k. - Reinhard Zumkeller (reinhard.zumkeller(AT)gmail.com), Aug 25 2002
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FORMULA
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a(n)=A000961(n+1)-A000961(n)
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EXAMPLE
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Odd differences arise in pairs in neighborhoods of powers of 2, like {..,2039,2048,2053,..} gives {..,11,5,..}
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PROGRAM
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Contribution from Michael Porter (michael_b_porter(AT)yahoo.com), Oct 30 2009: (Start)
(PARI) isA000961(n) = (omega(n) == 1 | n == 1)
n_prev=1; for(n=2, 500, if(isA000961(n), print(n-n_prev); n_prev=n)) (End)
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CROSSREFS
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Cf. A000961, A036616, A001223.
Sequence in context: A047060 A050167 A047050 this_sequence A054012 A062083 A133114
Adjacent sequences: A057817 A057818 A057819 this_sequence A057821 A057822 A057823
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KEYWORD
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nonn,new
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AUTHOR
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Labos E. (labos(AT)ana.sote.hu), Nov 08 2000
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