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A117861
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Number of palindromes of length n (in base 9).
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1
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8, 8, 72, 72, 648, 648, 5832, 5832, 52488, 52488, 472392, 472392, 4251528, 4251528, 38263752, 38263752, 344373768, 344373768, 3099363912, 3099363912, 27894275208, 27894275208, 251048476872, 251048476872, 2259436291848, 2259436291848, 20334926626632
(list; graph; refs; listen; history; internal format)
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OFFSET
| 1,1
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LINKS
| Harvey P. Dale, Table of n, a(n) for n = 1..1000
Index to sequences with linear recurrences with constant coefficients, signature (0,9).
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FORMULA
| a(n) = 8*9^floor((n-1)/2).
G.f.: 8*x*(1+x)/(1-9*x^2). a(n) = 8*3^(n-2)*(2-(-1)^n). - Bruno Berselli, Oct 24 2011
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MATHEMATICA
| Table[8 9^Floor[(n-1)/2], {n, 50}] (* From Harvey P. Dale, Oct 21 2011 *)
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CROSSREFS
| Cf. A050683.
Cf. A055275.
Sequence in context: A183395 A019216 A020552 * A186984 A082798 A192386
Adjacent sequences: A117858 A117859 A117860 * A117862 A117863 A117864
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KEYWORD
| nonn,base,easy
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AUTHOR
| Martin Renner (martin.renner(AT)gmx.net), May 02 2006
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EXTENSIONS
| More terms from Harvey P. Dale, Oct 21 2011
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