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Search: id:A123476
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| A123476 |
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(n!)^2/phi(n!), where phi is Euler's totient function. |
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+0
2
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| 1, 4, 18, 72, 450, 2700, 22050, 176400, 1587600, 15876000, 192099600, 2305195200, 32464832400, 454507653600, 6817614804000, 109081836864000, 1970290678356000, 35465232210408000, 711274934886516000
(list; graph; listen)
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OFFSET
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1,2
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COMMENT
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a(n) is a solution to the equation phi(x)=n!
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REFERENCES
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P. Erdos and J. Lambek, Problem 4221, Amer. Math. Monthly, 55 (1948), 103.
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LINKS
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T. D. Noe, Table of n, a(n) for n=1..100
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CROSSREFS
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Cf. A000010, A000142, A002202 (values taken by phi(x)).
Cf. A055487 (least m such that phi(m) = n!).
Adjacent sequences: A123473 A123474 A123475 this_sequence A123477 A123478 A123479
Sequence in context: A034352 A117615 A083693 this_sequence A027905 A037497 A075675
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KEYWORD
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nonn
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AUTHOR
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T. D. Noe (noe(AT)sspectra.com), Sep 27 2006
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