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Search: id:A110601
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| A110601 |
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phi(n)*tau(n)^2, where phi is Euler's totient function and tau(n) is the number of divisors of n. |
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+0
1
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| 1, 4, 8, 18, 16, 32, 24, 64, 54, 64, 40, 144, 48, 96, 128, 200, 64, 216, 72, 288, 192, 160, 88, 512, 180, 192, 288, 432, 112, 512, 120, 576, 320, 256, 384, 972, 144, 288, 384, 1024, 160, 768, 168, 720, 864, 352, 184, 1600, 378, 720, 512, 864, 208, 1152, 640
(list; graph; listen)
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OFFSET
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1,2
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REFERENCES
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S. Porubsky, Problem E2351, Amer. Math. Monthly, 80, 1973, p. 436.
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EXAMPLE
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a(4)=18 because phi(4)=2 and tau(4)=3.
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MAPLE
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with(numtheory): a:=n->phi(n)*tau(n)^2: seq(a(n), n=1..70);
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CROSSREFS
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Adjacent sequences: A110598 A110599 A110600 this_sequence A110602 A110603 A110604
Sequence in context: A098125 A119471 A075558 this_sequence A107926 A070213 A077474
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KEYWORD
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nonn
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AUTHOR
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Emeric Deutsch (deutsch(AT)duke.poly.edu), Jul 29 2005
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