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A131382
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Minimal number m such that Sum_digits(n*m)=n.
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5
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1, 1, 1, 1, 1, 1, 1, 1, 1, 19, 19, 4, 19, 19, 13, 28, 28, 11, 46, 199, 19, 109, 73, 37, 199, 73, 37, 271, 172, 1333, 289, 559, 1303, 847, 1657, 833, 1027, 1576, 1282, 17497, 4339, 2119, 2323, 10909, 11111, 12826, 14617, 14581, 16102, 199999, 17449, 38269
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OFFSET
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1,10
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LINKS
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H. Fredricksen, E. J. Ionascu, F. Luca, and P. Stanica, Minimal Niven numbers, arXiv:0803.0477 [math.NT], 2008.
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FORMULA
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EXAMPLE
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n=23 --> a=73 because 23*73 = 1679 and 1+6+7+9=23.
n=34 --> a=847 because 34*847 = 28798 and 2+8+7+9+8=34.
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MAPLE
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P:=proc(n) local i, j, k, w; for i from 1 by 1 to n do for j from 1 to n do w:=0; k:=i*j; while k>0 do w:=w+k-(trunc(k/10)*10); k:=trunc(k/10); od; if i=w then print(j); break; fi; od; od; end: P(1000000);
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MATHEMATICA
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m[n_]:=Module[{m=1}, While[Total[IntegerDigits[m*n]]!=n, m++]; m]; Array[m, 60] (* Harvey P. Dale, Sep 28 2013 *)
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PROG
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CROSSREFS
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KEYWORD
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base,nonn
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AUTHOR
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STATUS
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approved
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