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Search: id:A089903
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| A089903 |
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Sum of digits of numbers between 0 and (1/9)*(10^n-1). |
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+0
7
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| 0, 1, 48, 960, 14572, 195684, 2456796, 29567908, 345679020, 3956790132, 44567901244, 495679012356, 5456790123468, 59567901234580, 645679012345692, 6956790123456804, 74567901234567916, 795679012345679028
(list; graph; listen)
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OFFSET
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0,3
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COMMENT
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From a suggestion of Yalcin Aktar (aktaryalcin(AT)msn.com)
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FORMULA
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a(n)=s(1, n-1) where s(a, k)=a*(k+1)+a^2*sum(i=0, k, i*10^(k-i))+sum(i=0, k, 5*a*(9*(k-i)+a- 1)*10^(k-i-1))
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CROSSREFS
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Cf. A089904, A089905, A089906, A087330, A089907, A089908, A089909, A034967.
Sequence in context: A105948 A014401 A014703 this_sequence A160068 A010839 A000156
Adjacent sequences: A089900 A089901 A089902 this_sequence A089904 A089905 A089906
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KEYWORD
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nonn,base
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AUTHOR
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Benoit Cloitre (benoit7848c(AT)orange.fr), Nov 14 2003
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