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Search: id:A050250
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| A050250 |
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Number of nonzero palindromes less than 10^n. |
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+0
12
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| 9, 18, 108, 198, 1098, 1998, 10998, 19998, 109998, 199998, 1099998, 1999998, 10999998, 19999998, 109999998, 199999998, 1099999998, 1999999998, 10999999998, 19999999998, 109999999998, 199999999998, 1099999999998, 1999999999998, 10999999999998
(list; graph; listen)
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OFFSET
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1,1
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LINKS
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Dr. Math, More info 1
Dr. Math, More info 2
Eric Weisstein's World of Mathematics, Link to a section of The World of Mathematics.
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FORMULA
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a(2n)=2*10^n-2, a(2n+1)=11*10^n-2 - Sascha Kurz (sascha.kurz(AT)uni-bayreuth.de), Apr 14 2002
a(n) = Partial sum of A050683 = SUM[i=1..n] A050683(i) = SUM[i=1..n] 9*10^floor[(i-1)/2] = 9 * SUM[i=1..n] 10^floor[(i-1)/2]. - a(24)-a(25) from Jonathan Vos Post (jvospost3(AT)gmail.com), Jun 18 2008
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CROSSREFS
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Cf. A002113, A050683. Differences give A050683.
Cf. A050683.
Sequence in context: A140149 A066711 A033651 this_sequence A080453 A002169 A050685
Adjacent sequences: A050247 A050248 A050249 this_sequence A050251 A050252 A050253
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KEYWORD
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nonn,easy,base,nice
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AUTHOR
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Eric Weisstein (eric(AT)weisstein.com)
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EXTENSIONS
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More terms from Patrick De Geest (pdg(AT)worldofnumbers.com), 8/99.
a(24)-a(25) from Jonathan Vos Post (jvospost3(AT)gmail.com), Jun 18 2008
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