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Search: id:A071847
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| A071847 |
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Numbers n such that sigma(n) - sigma(reverse(n)) = phi(n). |
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+0
1
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| 1302, 6364, 13902, 30944, 35404, 57356, 88781, 132432, 141372, 183792, 284242, 555093, 806403, 1967262, 5010576, 5568948, 6298446, 7306241, 7496203, 7944911, 8078106
(list; graph; listen)
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OFFSET
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1,1
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EXAMPLE
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sigma(1302) - sigma(reverse(1302)) = sigma(1302) - sigma(2031) = 3072 - 2712 = 360 = phi(1302).
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MATHEMATICA
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r = {}; Do[ If[ DivisorSigma[1, n] - DivisorSigma[1, FromDigits[ Reverse[ IntegerDigits[n]]]] == EulerPhi[n], r = Append[r, n]], {n, 1, 10^7}]; r
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CROSSREFS
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Sequence in context: A135125 A022057 A107521 this_sequence A014356 A126841 A106815
Adjacent sequences: A071844 A071845 A071846 this_sequence A071848 A071849 A071850
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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), Jun 09 2002
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EXTENSIONS
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Edited and extended by Robert G. Wilson v (rgwv(AT)rgwv.com), Jun 11 2002
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