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Search: id:A084021
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| A084021 |
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Product of n and its 9's complement. |
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+0
3
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| 8, 14, 18, 20, 20, 18, 14, 8, 0, 890, 968, 1044, 1118, 1190, 1260, 1328, 1394, 1458, 1520, 1580, 1638, 1694, 1748, 1800, 1850, 1898, 1944, 1988, 2030, 2070, 2108, 2144, 2178, 2210, 2240, 2268, 2294, 2318, 2340, 2360, 2378, 2394, 2408, 2420, 2430, 2438
(list; graph; listen)
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OFFSET
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1,1
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COMMENT
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There are infinitely many nonzero squares in this sequence; for example a(10^(4n)-10^(2n)) = [10^n*(10^(2n)-1)]^2. - David Wasserman (wasserma(AT)spawar.navy.mil), Dec 07 2004
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FORMULA
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a(n) = n*(10^d -1-n), where d is the number of digits in n.
a(n) = n*A061601(n). - David Wasserman (wasserma(AT)spawar.navy.mil), Dec 07 2004
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CROSSREFS
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Cf. A061601.
Sequence in context: A082772 A103338 A050681 this_sequence A114456 A138666 A072835
Adjacent sequences: A084018 A084019 A084020 this_sequence A084022 A084023 A084024
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KEYWORD
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base,easy,nonn
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AUTHOR
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Amarnath Murthy (amarnath_murthy(AT)yahoo.com), May 23 2003
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EXTENSIONS
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More terms from David Wasserman (wasserma(AT)spawar.navy.mil), Dec 07 2004
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