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Search: id:A056789
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| A056789 |
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Sum_{k=1 to n} [LCM(k,n)/GCD(k,n)]. |
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+0
4
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| 1, 3, 10, 19, 51, 48, 148, 147, 253, 253, 606, 352, 1015, 738, 960, 1171, 2313, 1263, 3250, 1869, 2803, 3028, 5820, 2784, 6301, 5073, 6814, 5458, 11775, 4798, 14416, 9363, 11505, 11563, 14898, 9343, 24643, 16248, 19276, 14797, 33621, 14013, 38830
(list; graph; listen)
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OFFSET
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1,2
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COMMENT
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For odd prime n, a(n) = 1+p*p*(p-1)/2.
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LINKS
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T. D. Noe, Table of n, a(n) for n=1..1000
Leroy Quet, Home Page (listed in lieu of email address)
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EXAMPLE
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a(6) = 6/1 + 6/2 + 6/3 + 12/2 + 30/1 + 6/6 = 48.
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MATHEMATICA
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Table[ Sum[ LCM[k, n] / GCD[k, n], {k, 1, n}], {n, 1, 50}]
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CROSSREFS
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Row sums of triangle in A051537.
Sequence in context: A160002 A027177 A048343 this_sequence A098645 A089693 A005997
Adjacent sequences: A056786 A056787 A056788 this_sequence A056790 A056791 A056792
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KEYWORD
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nonn,nice
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AUTHOR
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Leroy Quet Aug 20 2000
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EXTENSIONS
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Additional comments from Amarnath Murthy (amarnath_murthy(AT)yahoo.com), May 09 2002
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