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Search: id:A071601
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| A071601 |
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Numbers n such that n and phi(n) have the same number of 1's in their binary representation. |
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+0
1
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| 1, 2, 4, 8, 9, 16, 18, 32, 33, 36, 49, 64, 65, 66, 69, 72, 77, 98, 99, 121, 128, 130, 132, 138, 141, 144, 145, 154, 169, 177, 196, 198, 209, 225, 242, 256, 260, 261, 264, 265, 276, 282, 288, 290, 297, 305, 308, 325, 338, 354, 361, 392, 396, 418, 441, 450, 484
(list; graph; listen)
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OFFSET
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1,2
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EXAMPLE
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676=1010100100 in base 2, phi(676)=312=100111000 in base 2, hence 676 is in the sequence.
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PROGRAM
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(PARI) for(n=1, 1000, if(sum(i=1, length(binary(n)), component(binary(n), i))==sum(i=1, length(binary(eulerphi(n))), component(binary(eulerphi(n)), i)), print1(n, ", ")))
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CROSSREFS
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Sequence in context: A155562 A048715 A028982 this_sequence A114400 A023898 A125853
Adjacent sequences: A071598 A071599 A071600 this_sequence A071602 A071603 A071604
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KEYWORD
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base,easy,nonn
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AUTHOR
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Benoit Cloitre (benoit7848c(AT)orange.fr), Jun 01 2002
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