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Search: id:A070856
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| A070856 |
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Numbers n such that sigma(reverse(n)) = phi(n). |
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+0
2
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| 1, 120, 260, 450, 861, 1411, 1541, 1550, 7372, 7957, 8393, 9312, 13811, 14840, 20440, 26060, 38323, 41550, 46990, 49813, 51412, 61050, 77695, 78625, 86691, 94604, 94632, 138631, 143520, 166331, 169360, 176820, 182750, 208150, 236220, 236840
(list; graph; listen)
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OFFSET
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1,2
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EXAMPLE
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sigma(reverse(120)) = simga(21) = 32 = phi(120), so 120 is a term of the sequence.
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MATHEMATICA
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Select[ Range[ 10^6 ], EulerPhi[ # ]==DivisorSigma[ 1, FromDigits[ Reverse[ IntegerDigits[ # ] ] ] ]& ]
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CROSSREFS
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Cf. A070835.
Sequence in context: A146950 A028976 A158130 this_sequence A000804 A076579 A121898
Adjacent sequences: A070853 A070854 A070855 this_sequence A070857 A070858 A070859
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KEYWORD
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base,nonn
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AUTHOR
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Joseph L. Pe (joseph_l_pe(AT)hotmail.com), May 16 2002
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EXTENSIONS
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Extended by Ray Chandler (rayjchandler(AT)sbcglobal.net), Feb 10 2009
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