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A004155
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Sum of digits of n-th odd number.
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2
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1, 3, 5, 7, 9, 2, 4, 6, 8, 10, 3, 5, 7, 9, 11, 4, 6, 8, 10, 12, 5, 7, 9, 11, 13, 6, 8, 10, 12, 14, 7, 9, 11, 13, 15, 8, 10, 12, 14, 16, 9, 11, 13, 15, 17, 10, 12, 14, 16, 18, 2, 4, 6, 8, 10, 3, 5, 7, 9, 11, 4, 6, 8, 10, 12, 5
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OFFSET
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0,2
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LINKS
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FORMULA
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a(n) = 2n - 1 - 9*Sum_{k=1..1+floor(log_10(2n-1))} floor( (n-1)/(5*10^(k-1)) ). - Anthony Browne, Jun 18 2016
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MATHEMATICA
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Table[Sum[DigitCount[2*n + 1][[i]]*i, {i, 9}], {n, 0, 100}] (* G. C. Greubel, Jun 19 2016 *)
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PROG
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CROSSREFS
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KEYWORD
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nonn,base,easy
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AUTHOR
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STATUS
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approved
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