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A178323
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Numbers n such that phi(reversal(n)) + sigma(reversal(n)) = n.
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0
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OFFSET
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1,1
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COMMENTS
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If n is in the sequence A070272 then reversal(n) is in this sequence. 10 divides all other terms of the sequence. 2014080 is the only known such term.
If p=6*10^n-1 is a prime greater than 5 then reversal(5*p) is in the sequence, see comment lines of A070272.
There is no further term up to 10^9.
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LINKS
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EXAMPLE
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2014080 = phi(804102) + sigma(804102), so 2014080 is in the sequence.
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MATHEMATICA
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r[n_]:=FromDigits[Reverse[IntegerDigits[n]]];
Do[If[EulerPhi[r[n]]+DivisorSigma[1, r[n]]==n, Print[n]], {n, 1000000000}]
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CROSSREFS
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KEYWORD
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nonn,base,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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