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Search: id:A164089
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| A164089 |
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For n >=4, a(n) = the numerical value of the substring of binary n containing all digits but the first and last. a(1) = a(2) = a(3) = 0. |
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+0
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| 0, 0, 0, 0, 0, 1, 1, 0, 0, 1, 1, 2, 2, 3, 3, 0, 0, 1, 1, 2, 2, 3, 3, 4, 4, 5, 5, 6, 6, 7, 7, 0, 0, 1, 1, 2, 2, 3, 3, 4, 4, 5, 5, 6, 6, 7, 7, 8, 8, 9, 9, 10, 10, 11, 11, 12, 12, 13, 13, 14, 14, 15, 15, 0, 0, 1, 1, 2, 2, 3, 3, 4, 4, 5, 5, 6, 6, 7, 7, 8, 8, 9, 9, 10, 10, 11, 11, 12, 12, 13, 13, 14, 14, 15
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OFFSET
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1,12
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COMMENT
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a(2n) = a(2n+1) for all n.
For m >=2, terms a(2^m) through a(2^(m+1)-1) are 0,0,1,1,2,2,3,3,..., 2^(m-1)-1, 2^(m-1)-1.
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EXAMPLE
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26 in binary is 11010. Take the middle digits 1(101)0 - > 101, which is 5 in decimal. Therefore a(26) = 5.
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CROSSREFS
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Sequence in context: A127012 A125503 A127009 this_sequence A068460 A143797 A079729
Adjacent sequences: A164086 A164087 A164088 this_sequence A164090 A164091 A164092
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KEYWORD
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base,easy,nonn
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AUTHOR
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Leroy Quet (q1qq2qqq3qqqq(AT)yahoo.com), Aug 09 2009
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