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Search: id:A091860
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| A091860 |
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a(1)=1, a(n)=sum(i=1,n-1,b(i)) where b(i)=0 if a(i) and a(n-i) are both even, b(i)=1 otherwise. |
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+0
1
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| 1, 1, 2, 3, 4, 4, 6, 5, 6, 6, 8, 6, 8, 8, 8, 7, 8, 8, 10, 8, 10, 10, 10, 8, 10, 10, 10, 10, 10, 10, 10, 9, 10, 10, 12, 10, 12, 12, 12, 10, 12, 12, 12, 12, 12, 12, 12, 10, 12, 12, 12, 12, 12, 12, 12, 12, 12, 12, 12, 12, 12, 12, 12, 11, 12, 12, 14, 12, 14, 14, 14, 12, 14, 14, 14, 14, 14
(list; graph; listen)
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OFFSET
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1,3
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FORMULA
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n>1 a(2n)=a(n)+2; if n is a power of 2, a(2n+1)=1+a(2n); if n is the sum of 2 distinct power of 2, a(2n+1)=2+a(2n); a(2n+1)=a(2n) otherwise
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PROGRAM
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(PARI) an[1]=1; for(n=2, 100, an[n]=sum(i=1, n-1, max(a(i)%2, a(n-i)%2)))
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CROSSREFS
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Cf. A018900, A072823.
Sequence in context: A008329 A064558 A008328 this_sequence A158973 A071323 A071324
Adjacent sequences: A091857 A091858 A091859 this_sequence A091861 A091862 A091863
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KEYWORD
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nonn
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AUTHOR
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Benoit Cloitre (benoit7848c(AT)orange.fr), Mar 16 2004
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