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A140807
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a(n) = the largest integer such that n^k is palindromic in binary for all nonnegative integers k that are <= a(n).
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0
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0, 3, 0, 1, 0, 1, 0, 1, 0, 0, 0, 0, 0, 1, 0, 1, 0, 0, 0, 1, 0, 0, 0, 0, 0, 1, 0, 0, 0, 1, 0, 1, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 1, 0, 0, 0, 0, 0, 1, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 1, 0, 1, 0, 0, 0, 0, 0, 0, 0, 1, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 1, 0, 0, 0, 0, 0, 0, 0, 1, 0, 0, 0, 0, 0, 1, 0
(list; graph; refs; listen; history; internal format)
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OFFSET
| 2,2
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COMMENTS
| a(2n) = 0 for all n.
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FORMULA
| For n>3, a(n)=0 or 1; moreover, a(n)=1 iff n belongs to A006995 (in other words, this sequence is an indicator function of A006995). - Max Alekseyev (maxale(AT)gmail.com), Jul 22 2008
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EXAMPLE
| The powers of 3 are, when written in binary: 1, 11, 1001, 11011, 1010001,... Now, 3^k written in binary is palindromic for k = 0,1,2 and 3, but not for k=4. So a(3) = 3.
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CROSSREFS
| Cf. A006995.
Sequence in context: A106216 A035676 A129685 * A091959 A046094 A055976
Adjacent sequences: A140804 A140805 A140806 * A140808 A140809 A140810
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KEYWORD
| nonn,base
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AUTHOR
| Leroy Quet Jul 15 2008
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EXTENSIONS
| More terms from Max Alekseyev (maxale(AT)gmail.com), Jul 22 2008
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