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Search: id:A087550
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| A087550 |
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a(n) = smallest k such that for each r, 2 <= r <= n, there exists a distinct s, n < s <= k, with the same prime signature as r. |
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+0
1
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| 3, 7, 9, 13, 13, 19, 27, 49, 49, 49, 49, 49, 49, 49, 81, 81, 81, 81, 81, 81, 81, 81, 81, 169, 169, 343, 343, 343, 343, 343, 343, 343, 343, 343, 343, 343, 343, 343, 343, 343, 343, 343, 343, 343, 343, 343, 343, 361, 361, 361, 361, 361, 361, 361, 361, 361, 361, 361
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OFFSET
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2,1
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FORMULA
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For sufficiently large n, a(n) = 7^floor(log(n)/log(3)) because log(prime(2m))/log(prime(m)) is largest for m = 2. - David Wasserman (wasserma(AT)spawar.navy.mil), Jun 03 2005
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EXAMPLE
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a(7) = 19 and For numbers ( 2,3,4,5,6,7) we have the set of numbers ( 11,13,9,17,10,19) with matching prime signatures.
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CROSSREFS
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Sequence in context: A085074 A110404 A087064 this_sequence A047241 A086515 A132222
Adjacent sequences: A087547 A087548 A087549 this_sequence A087551 A087552 A087553
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KEYWORD
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nonn
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AUTHOR
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Amarnath Murthy (amarnath_murthy(AT)yahoo.com), Sep 13 2003
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EXTENSIONS
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More terms from David Wasserman (wasserma(AT)spawar.navy.mil), Jun 03 2005
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