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A358509
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Sum of decimal digits of (3^n - 1)/2 (A003462).
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2
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0, 1, 4, 4, 4, 4, 13, 13, 13, 22, 22, 31, 22, 31, 31, 31, 22, 31, 31, 31, 31, 31, 49, 49, 40, 40, 49, 67, 58, 58, 58, 76, 58, 76, 85, 85, 85, 85, 94, 85, 85, 94, 103, 103, 85, 94, 103, 112, 103, 112, 130, 130, 94, 121, 112, 112, 121, 103, 103, 121, 112, 121, 121, 139, 121, 148, 121, 157, 157, 157, 157, 175, 157, 157
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OFFSET
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0,3
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COMMENTS
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LINKS
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FORMULA
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EXAMPLE
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For n=5, (3^n - 1)/2 = 121 so that a(5) = 1+2+1 = 4.
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MAPLE
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seq(convert(convert((3^n-1)/2, base, 10), `+`), n=0..100); # Robert Israel, Nov 21 2022
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MATHEMATICA
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a[n_] := Total[IntegerDigits[(3^n - 1)/2]]; Array[a, 100, 0] (* Amiram Eldar, Nov 20 2022 *)
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PROG
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(PARI) a(n) = sumdigits((3^n - 1)/2); \\ Michel Marcus, Nov 20 2022
(Python)
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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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