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Search: id:A071600
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| A071600 |
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Numbers n such that n and prime(n) have the same number of 1's in their binary representation. |
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+0
8
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| 1, 3, 13, 19, 21, 23, 25, 30, 44, 45, 47, 57, 60, 61, 71, 77, 98, 99, 101, 103, 107, 108, 110, 118, 121, 125, 158, 159, 178, 179, 184, 186, 187, 188, 209, 215, 218, 221, 237, 244, 246, 247, 248, 249, 251, 279, 287, 312, 334, 335, 346, 350, 359, 361, 362, 365
(list; graph; listen)
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OFFSET
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1,2
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COMMENT
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a(n) = A049084(A072439(n)); A000120(a(n)) = A000120(A072439(n)) = A014499(n). - Reinhard Zumkeller (reinhard.zumkeller(AT)gmail.com), Jun 17 2002
A090455(a(n))=0, A000120(a(n))=A014499(a(n)).
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EXAMPLE
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221=11011101 in base 2, prime(221)=1381=10101100101 in base 2, both have 6 "1's" in their binary representation, hence 221 is in the sequence.
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PROGRAM
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(PARI) for(n=1, 1000, s=1; if(sum(i=1, length(binary(n)), component(binary(n), i))==sum(i=1, length(binary(prime(n))), component(binary(prime(n)), i)), print1(n, ", ")))
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CROSSREFS
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Cf. A033549.
Adjacent sequences: A071597 A071598 A071599 this_sequence A071601 A071602 A071603
Sequence in context: A024685 A024474 A024599 this_sequence A045435 A038974 A079419
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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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