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Search: id:A069747
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| A069747 |
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Numbers n such that n and phi(n) are both palindromes. |
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+0
1
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| 1, 2, 3, 4, 5, 6, 7, 8, 9, 535, 767, 20502, 50805, 53035, 58085, 58585, 59395, 82428, 88188, 3269623, 5808085, 5846485, 8110118, 8666668, 8818188, 8872788, 8875788
(list; graph; listen)
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OFFSET
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1,2
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COMMENT
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For an arithmetical function f, call the pairs (x,y) such that y = f(x) and x, y are palindromes the "palinpairs" of f. a(n) is then the sequence of abcissae of palinpairs of f(n) = phi(n).
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EXAMPLE
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phi(58085) = 46464, so 58085 is a term of the sequence.
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MATHEMATICA
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isPalin[n_] := (n == FromDigits[Reverse[IntegerDigits[n]]]); Do[m = EulerPhi[n]; If[isPalin[n] && isPalin[m], Print[{n, m}]], {n, 1, 10^6}]
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CROSSREFS
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Sequence in context: A046469 A004893 A069282 this_sequence A124107 A112014 A145461
Adjacent sequences: A069744 A069745 A069746 this_sequence A069748 A069749 A069750
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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), Apr 22 2002
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EXTENSIONS
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More terms from Jason Earls (zevi_35711(AT)yahoo.com), May 07 2002
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