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Search: id:A125857
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| A125857 |
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Numbers whose base 9 representation is 22222222.......2. |
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+0
1
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| 0, 2, 20, 182, 1640, 14762, 132860, 1195742, 10761680, 96855122, 871696100, 7845264902, 70607384120, 635466457082, 5719198113740, 51472783023662, 463255047212960, 4169295424916642, 37523658824249780, 337712929418248022
(list; graph; listen)
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OFFSET
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0,2
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FORMULA
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a(n)=(9^n-1)*2/8.
a(n)=9*a(n-1)+2 (with a(1)=0) [From Vincenzo Librandi (vincenzo.librandi(AT)tin.it), Oct 30 2009]
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EXAMPLE
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For n=2, a(2)=9*0+2=2; n=3, a(3)=9*2+2=20; n=4, a(4)=9*20+2=182 [From Vincenzo Librandi (vincenzo.librandi(AT)tin.it), Oct 30 2009]
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MAPLE
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seq((9^n-1)*2/8, n=0..19);
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CROSSREFS
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Sequence in context: A105493 A067641 A037566 this_sequence A001078 A001253 A085586
Adjacent sequences: A125854 A125855 A125856 this_sequence A125858 A125859 A125860
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KEYWORD
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easy,nonn,new
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AUTHOR
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Zerinvary Lajos (zerinvarylajos(AT)yahoo.com), Feb 03 2007
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