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Search: id:A099767
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| A099767 |
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Number of n-digit palindromes in base n. |
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+0
1
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| 1, 6, 12, 100, 180, 2058, 3584, 52488, 90000, 1610510, 2737152, 57921708, 97883968, 2392031250, 4026531840, 111612119056, 187339329792, 5808378560022, 9728000000000
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OFFSET
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2,2
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FORMULA
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a(n) = (n - 1)*n^([(n + 1)/2] - 1) where [] is the greatest integer function
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EXAMPLE
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a(3) = 6 because there are 6 3-digit palindromes in base 3, namely 101, 111, 121, 202, 212, 222.
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MATHEMATICA
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(n - 1)*n^(Floor[(n + 1)/2] - 1) /. n -> Range[2, 20]
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CROSSREFS
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Sequence in context: A128953 A002898 A003613 this_sequence A080450 A095388 A038515
Adjacent sequences: A099764 A099765 A099766 this_sequence A099768 A099769 A099770
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KEYWORD
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easy,nonn
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AUTHOR
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Anonymous, Nov 11 2004
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