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A030301
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n-th run has length 2^(n-1).
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4
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0, 1, 1, 0, 0, 0, 0, 1, 1, 1, 1, 1, 1, 1, 1, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0
(list; graph; refs; listen; history; internal format)
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OFFSET
| 1,1
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FORMULA
| a(n) = 0 iff n has an odd number of digits in binary, = 1 otherwise - Henry Bottomley (se16(AT)btinternet.com), Apr 06 2000
a(n) = (1/2)*{1-(-1)^floor(ln(n)/ln(2))}. - Benoit Cloitre (benoit7848c(AT)orange.fr), Nov 22 2001
a(n)=1-a(floor(n/2)). - Vladeta Jovovic (vladeta(AT)eunet.rs), Aug 04 2003
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PROG
| (PARI) a(n)=if(n<1, 0, 1-length(binary(n))%2)
(PARI) a(n)=if(n<1, 0, if(n%2==0, -a(n/2)+1, -a((n-1)/2)+1-(((n-1)/2)==0))) (from R. Stephan)
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CROSSREFS
| a(n) = A000523(n) mod 2 = (A029837(n+1)+1) mod 2.
Cf. A030300. Partial sums give A079954.
Sequence in context: A171386 A125720 A095130 * A071981 A093692 A105384
Adjacent sequences: A030298 A030299 A030300 * A030302 A030303 A030304
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KEYWORD
| nonn,easy
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AUTHOR
| Jean-Paul Delahaye (Jean-Paul.Delahaye(AT)lifl.fr)
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