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Search: id:A109668
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| A109668 |
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Numbers n such that the sum of the digits of phi(n)^sigma(n) is divisible by n. |
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+0
1
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| 1, 9, 18, 35, 67, 189, 310, 475, 516, 684, 2493, 2527, 3465, 4701, 5157, 8321
(list; graph; listen)
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OFFSET
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1,2
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EXAMPLE
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The digits of phi(3465)^sigma(3465) sum to 72765 and 72765 is divisible by 3465, so 3465 is in the sequence.
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MATHEMATICA
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Do[s = EulerPhi[n]^DivisorSigma[1, n]; k = Plus @@ IntegerDigits[s]; If[Mod[k, n] == 0, Print[n]], {n, 1, 10^4}]
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CROSSREFS
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Sequence in context: A161570 A140089 A139591 this_sequence A051063 A162689 A033896
Adjacent sequences: A109665 A109666 A109667 this_sequence A109669 A109670 A109671
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KEYWORD
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base,more,nonn
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AUTHOR
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Ryan Propper (rpropper(AT)stanford.edu), Aug 06 2005
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