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Search: id:A089904
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| A089904 |
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Sum of digits of numbers between 0 and (2/9)*(10^n-1). |
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+0
7
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| 0, 3, 109, 2055, 30501, 404947, 5049393, 60493839, 704938285, 8049382731, 90493827177, 1004938271623, 11049382716069, 120493827160515, 1304938271604961, 14049382716049407, 150493827160493853
(list; graph; listen)
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OFFSET
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0,2
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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(2, 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. A089903, A089905, A089906, A087330, A089907, A089908, A089909, A034967.
Sequence in context: A053861 A041635 A142533 this_sequence A092252 A114738 A111091
Adjacent sequences: A089901 A089902 A089903 this_sequence A089905 A089906 A089907
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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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