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A004166
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Sum of digits of 3^n.
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25
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1, 3, 9, 9, 9, 9, 18, 18, 18, 27, 27, 27, 18, 27, 45, 36, 27, 27, 45, 36, 45, 27, 45, 54, 54, 63, 63, 81, 72, 72, 63, 81, 63, 72, 99, 81, 81, 90, 90, 81, 90, 99, 90, 108, 90, 99, 108, 126, 117, 108, 144, 117, 117, 135, 108, 90, 90, 108, 126, 117, 99
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OFFSET
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0,2
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COMMENTS
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All terms a(n), n > 1, are divisible by 9. - M. F. Hasler, Sep 27 2017
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LINKS
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FORMULA
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MATHEMATICA
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Total[IntegerDigits[#]]&/@(3^Range[0, 60]) (* Harvey P. Dale, Mar 03 2013 *)
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PROG
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(Python)
def a(n): return sum(map(int, str(3**n)))
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CROSSREFS
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Cf. sum of digits of k^n: A001370 (k=2), this sequence (k=3), A065713 (k=4), A066001 (k=5), A066002 (k=6), A066003 (k=7), A066004 (k=8), A065999 (k=9), A066005 (k=11), A066006 (k=12), A175527 (k=13).
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KEYWORD
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nonn,base
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AUTHOR
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EXTENSIONS
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STATUS
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approved
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