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A209192
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Numbers n such that digital root of n equals largest prime factor of n.
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1
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2, 3, 5, 7, 12, 48, 50, 70, 128, 192, 196, 320, 448, 500, 700, 768, 1960, 2401, 3072, 3200, 4480, 5000, 5488, 7000, 8192, 8575, 12288, 12544, 19600, 20480, 24010, 28672, 30625, 32000, 44800, 49152, 50000, 54880, 67228, 70000, 78125, 85750, 109375, 125440
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internal format)
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OFFSET
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1,1
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LINKS
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MAPLE
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d := (add(d, d=convert(n, base, 10))) mod 9 ;
if d = 0 then
return 9;
else
return d;
end if;
end proc:
isA209192 := proc(n)
end proc:
for n from 2 to 40000 do if isA209192(n) then printf("%d, ", n) ; end if; end do: # R. J. Mathar, Mar 22 2012
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CROSSREFS
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KEYWORD
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nonn,base
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AUTHOR
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STATUS
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approved
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