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Search: id:A061026
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| A061026 |
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Smallest number m such that phi(m) is divisible by n, where phi = Euler totient function A000010. |
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+0
4
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| 1, 3, 7, 5, 11, 7, 29, 15, 19, 11, 23, 13, 53, 29, 31, 17, 103, 19, 191, 25, 43, 23, 47, 35, 101, 53, 81, 29, 59, 31, 311, 51, 67, 103, 71, 37, 149, 191, 79, 41, 83, 43, 173, 69, 181, 47, 283, 65, 197, 101, 103, 53, 107, 81, 121, 87, 229, 59, 709, 61, 367, 311, 127, 85
(list; graph; listen)
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OFFSET
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1,2
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REFERENCES
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M. J. Knight, Comment with Solution to 10837, American Mathematical Monthly, 2001.
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LINKS
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T. D. Noe, Table of n, a(n) for n=1..1000
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FORMULA
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Sequence is unbounded; a(n) <= n^2 since phi(n^2) is always divisible by n.
If n+1 is prime a(n)=n+1.
a(n) = min( k : phi(k) == 0 mod(n) )
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EXAMPLE
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a(48) = 65 because phi(65) = phi(5)phi(13) = (4)(12) = 48 and no smaller integer has phi(n) = 48.
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PROGRAM
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(PARI) for(n=1, 100, s=1; while(eulerphi(s)%n>0, s++); print1(s, ", "))
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CROSSREFS
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Cf. A000010, A066674-A066676, A066678, A067005.
Sequence in context: A094009 A088514 A066677 this_sequence A064632 A090978 A113830
Adjacent sequences: A061023 A061024 A061025 this_sequence A061027 A061028 A061029
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KEYWORD
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nonn
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AUTHOR
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Melvin J. Knight (knightmj(AT)juno.com), May 25 2001
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