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A066278
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Least solution to cototient(x) = n!, where cototient(x) = x-phi(x).
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0
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2, 4, 10, 36, 168, 1008, 7056, 56448, 470400, 4704000, 51528960, 618347520, 7740902400, 108372633600
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OFFSET
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1,1
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COMMENTS
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a(15) <= 1625589504000. a(16) <= 26009432064000. a(17) <= 442160345088000. [Donovan Johnson, Feb 05 2010]
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LINKS
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FORMULA
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EXAMPLE
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Solutions to x-Phi[x]=720 are {1008,1424,1432,1436,1438} of which the smallest is a(6)=1008.
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PROG
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(PARI) a(n) = my(x=1); while(x-eulerphi(x) != n!, x++); x; \\ Michel Marcus, Aug 24 2019
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CROSSREFS
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KEYWORD
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nonn,more
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AUTHOR
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EXTENSIONS
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STATUS
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approved
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