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Search: id:A056641
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| A056641 |
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Least positive integer k for which (b+1)^k is not palindromic in base b, b = 2, 3, 4, ... |
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+0
1
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| 4, 3, 4, 4, 4, 5, 5, 5, 5, 6, 6, 6, 6, 6, 6, 6, 6, 6, 6, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 9, 9, 9, 9, 9, 9, 9, 9, 9, 9, 9, 9, 9, 9, 9, 9, 9, 9, 9, 9, 9
(list; graph; listen)
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OFFSET
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0,1
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COMMENT
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Sequence of run lengths is C(n,[ (n-1)/2 ]) (= A037952), n=1,2,3,...; sequence of b where a(b) != a(b-1), b >= 3, is C(b-1,[ (b-1)/2 ]) (= A001405).
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EXAMPLE
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The 4-th term is 4 because base 5 representations of (5+1)^1 = 11, (5+1)^2 = 121, (5+1)^3 = 1331, are all palindromic, while (5+1)^4 = 20141 is not.
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CROSSREFS
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Cf. A037952, A001405.
Sequence in context: A088910 A010308 A084596 this_sequence A010652 A088752 A049788
Adjacent sequences: A056638 A056639 A056640 this_sequence A056642 A056643 A056644
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KEYWORD
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nonn
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AUTHOR
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Helge Robitzsch (hrobi(AT)math.uni-goettingen.de), Aug 11 2000
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