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A054031
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Numbers whose square contains exactly 3 distinct digits.
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10
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13, 14, 16, 17, 18, 19, 23, 24, 25, 27, 28, 29, 31, 34, 35, 39, 40, 41, 45, 46, 47, 50, 56, 58, 60, 62, 63, 65, 67, 68, 70, 75, 76, 77, 80, 81, 83, 85, 90, 91, 92, 94, 97, 101, 102, 107, 108, 110, 111, 119, 120, 121, 122, 129, 131, 141, 149, 150, 162, 165
(list;
graph;
refs;
listen;
history;
text;
internal format)
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OFFSET
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1,1
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LINKS
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Giovanni Resta, Table of n, a(n) for n = 1..12299 (terms < 10^18, first 1000 terms from T. D. Noe)
Michael Geißer, Theresa Körner, Sascha Kurz, and Anne Zahn, Squares with three digits
Carlos Rivera, Puzzle 313. Squares having only k distinct digits, The Prime Puzzles and Problems Connection.
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FORMULA
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A235718(n) = a(n)^2. - Giovanni Resta, Apr 28 2017
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MAPLE
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f := []; for i from 0 to 200 do if nops({op(convert(i^2, base, 10))})=3 then f := [op(f), i] fi; od; f;
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MATHEMATICA
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t = {}; n = -1; While[Length[t] < 50, n++; If[Length[Union[IntegerDigits[n^2]]] == 3, AppendTo[t, n]]] (* T. D. Noe, Apr 26 2013 *)
Select[Range[200], Length[Union[IntegerDigits[#^2]]]==3&] (* Harvey P. Dale, Aug 17 2014 *)
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PROG
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(PARI) is(n)=#Set(digits(n^2))==3 \\ Charles R Greathouse IV, Feb 11 2017
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CROSSREFS
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Cf. A235718, A016069, A054032, A054033, A054034, A054035, A054036, A054037, A054038, A054039.
Sequence in context: A048037 A346657 A171492 * A060275 A083984 A272022
Adjacent sequences: A054028 A054029 A054030 * A054032 A054033 A054034
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KEYWORD
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nonn,base
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AUTHOR
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Asher Auel (asher.auel(AT)reed.edu), Feb 29 2000
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STATUS
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approved
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