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Search: id:A137331
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| A137331 |
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a(n) = 1 if the binary weight of n is prime, otherwise 0. |
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+0
1
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| 0, 0, 0, 1, 0, 1, 1, 1, 0, 1, 1, 1, 1, 1, 1, 0, 0, 1, 1, 1, 1, 1, 1, 0, 1, 1, 1, 0, 1, 0, 0, 1, 0, 1, 1, 1, 1, 1, 1, 0, 1, 1, 1, 0, 1, 0, 0, 1, 1, 1, 1, 0, 1, 0, 0, 1, 1, 0, 0, 1, 0, 1, 1, 0, 0, 1, 1, 1, 1, 1, 1, 0, 1, 1, 1, 0, 1, 0, 0, 1, 1, 1, 1, 0, 1, 0, 0, 1, 1, 0, 0, 1, 0, 1, 1, 0, 1, 1, 1, 0, 1, 0, 0, 1, 1
(list; graph; listen)
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OFFSET
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0,1
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FORMULA
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a(n) = A010051(A000120(n)). - R. J. Mathar (mathar(AT)strw.leidenuniv.nl), Apr 09 2008
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EXAMPLE
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a(0) = 0 (binary). Bits set = 0, 0 not prime -> 0.
a(1) = 1 (binary). Bits set = 1, 1 not prime -> 0.
a(2) = 10 (binary). Bits set = 1, 1 not prime -> 0.
a(3) = 11 (binary). Bits set = 2, 2 prime -> 1.
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MAPLE
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A000120 := proc(n) add(i, i=convert(n, base, 2)) ; end: A010051 := proc(n) if isprime(n) then 1 ; else 0 ; fi ; end: A137331 := proc(n) A010051(A000120(n)) ; end: seq(A137331(n), n=0..200) ; - R. J. Mathar (mathar(AT)strw.leidenuniv.nl), Apr 09 2008
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MATHEMATICA
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Table[If[PrimeQ[Plus @@ IntegerDigits[n, 2]], 1, 0], {n, 0, 100}] - Stefan Steinerberger (stefan.steinerberger(AT)gmail.com), Apr 09 2008
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CROSSREFS
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Begins the same as A135136, but differs starting at a(31).
Adjacent sequences: A137328 A137329 A137330 this_sequence A137332 A137333 A137334
Sequence in context: A095792 A093385 A135136 this_sequence A093386 A011658 A135461
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KEYWORD
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nonn,easy
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AUTHOR
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George Pollard (porges(AT)porg.es), Apr 07 2008
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EXTENSIONS
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More terms from R. J. Mathar (mathar(AT)strw.leidenuniv.nl) and Stefan Steinerberger (stefan.steinerberger(AT)gmail.com), Apr 09 2008
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