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A256709
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Numbers n such that the decimal expansions of both n and n^2 have 0 as smallest digit and 9 as largest digit.
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23
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509, 890, 903, 905, 930, 950, 960, 970, 980, 990, 1039, 1091, 1095, 1097, 1390, 1709, 1903, 1905, 1930, 1970, 1980, 1990, 2049, 2093, 2095, 2097, 2190, 2509, 2809, 2903, 2905, 2907, 2930, 2970, 2990, 3009, 3049, 3079, 3090, 3092, 3095, 3097, 3098, 3099, 3209
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OFFSET
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1,1
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LINKS
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MATHEMATICA
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fQ[n_] := Block[{c = DigitCount@ n}, And[c[[9]] > 0, c[[10]] > 0]]; Select[Range@ 3209, fQ@ # && fQ[#^2] &] (* Michael De Vlieger, Apr 12 2015 *)
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PROG
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(PARI) is(n) = vecmin(digits(n))==0 && vecmin(digits(n^2))==0 && vecmax(digits(n))==9 && vecmax(digits(n^2))==9
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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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