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A199987
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Numbers with digital product = 4.
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3
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4, 14, 22, 41, 114, 122, 141, 212, 221, 411, 1114, 1122, 1141, 1212, 1221, 1411, 2112, 2121, 2211, 4111, 11114, 11122, 11141, 11212, 11221, 11411, 12112, 12121, 12211, 14111, 21112, 21121, 21211, 22111, 41111, 111114, 111122, 111141, 111212, 111221, 111411
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refs;
listen;
history;
text;
internal format)
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OFFSET
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1,1
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COMMENTS
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LINKS
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MAPLE
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f:= proc(d) local b, i, t;
b:= (10^d-1)/9;
op(sort([seq(b+3*10^i, i=0..d-1),
seq(b+10^t[1]+10^t[2], t=combinat:-choose([$0..d-1], 2))]))
end proc:
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MATHEMATICA
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Select[Range[200000], Times @@ IntegerDigits[#] == 4 &] (* T. D. Noe, Nov 16 2011 *)
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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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