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Search: id:A162742
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| A162742 |
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Reverse digits in the binary representation of each prime base in the prime factorization of n. |
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+0
2
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| 1, 1, 3, 1, 5, 3, 7, 1, 9, 5, 13, 3, 11, 7, 15, 1, 17, 9, 25, 5, 21, 13, 29, 3, 25, 11, 27, 7, 23, 15, 31, 1, 39, 17, 35, 9, 41, 25, 33, 5, 37, 21, 53, 13, 45, 29, 61, 3, 49, 25, 51, 11, 43, 27, 65, 7, 75, 23, 55, 15, 47, 31, 63, 1, 55, 39, 97, 17, 87, 35, 113, 9, 73, 41, 75, 25, 91, 33
(list; graph; listen)
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OFFSET
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1,3
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COMMENT
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Base-2 variant of A071786: apply the bit-reversion A030101 to each of the primes in the bases of the prime factorization of n.
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FORMULA
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A161955(n)=A030101(a(n)).
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EXAMPLE
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At n=8=2^3, represent 2 as 10 in binary, reverse 10 to give 1, and recombine as 1^3=1 = a(8). At n=14=2*7 =(10)*(111) in binary, reverse the factors to give (1)*(111)=1*7=7=a(14).
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MAPLE
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A030101 := proc(n) local dgs ; dgs := convert(n, base, 2) ; add( op(-i, dgs)*2^(i-1), i=1..nops(dgs)) ; end: a := proc(n) local a, p ; a := 1 ; for p in ifactors(n)[2] do a := a* A030101(op(1, p))^op(2, p) ; od: a; end: seq(a(n), n=1..120) ;
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CROSSREFS
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Sequence in context: A106609 A093474 A030101 this_sequence A081432 A136655 A060819
Adjacent sequences: A162739 A162740 A162741 this_sequence A162743 A162744 A162745
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KEYWORD
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base,easy,nonn
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AUTHOR
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R. J. Mathar (mathar(AT)strw.leidenuniv.nl), Jul 12 2009
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EXTENSIONS
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Cleaned up the definition and corrected the second example - R. J. Mathar (mathar(AT)strw.leidenuniv.nl), Aug 03 2009
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