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Search: id:A132391
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| A132391 |
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Numbers whose square starts with 4 identical digits. |
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+0
3
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| 2357, 2582, 3334, 4714, 5774, 6667, 8165, 8819, 9428, 10541, 10542, 10543, 10544, 10545, 14907, 14908, 14909, 18257, 18258, 18259, 21081, 21082, 21083, 23570, 23571, 25819, 25820, 27888, 27889, 29813, 29814, 31622, 33332, 33333
(list; graph; listen)
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OFFSET
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1,1
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EXAMPLE
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Example: 2357^2 = 5555449.
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MATHEMATICA
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Select[Range[10, 50000], Length[Union[Take[IntegerDigits[ #^2], 4]]] == 1 & ]
Comment from Hans Havermann (pxp(AT)rogers.com), Aug 30 2007: Here's a more generic Mathematica program that calculates the first q terms of squares starting with n identical digits:
n=4; q=30; t=Table[(10^n-1)*i/9, {i, 1, 9}]; u=Sqrt[Union[t, 10*t]];
v=Sqrt[Union[t+1, 10*(t+1)]]; k=1; While[s=Sort[Flatten[Table[Union
[Table[Range[Ceiling[10^j*u[[i]]], f=10^j*v[[i]]; If[IntegerQ[f],
f=f-1]; Floor[f]], {i, 1, 18}]], {j, 0, k}]]]; Length[s]<q, k++ ]; Take[s, q]
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CROSSREFS
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Cf. A119887, A119511, A131573, A119866, A133183.
Sequence in context: A063517 A035874 A136420 this_sequence A134966 A108419 A073037
Adjacent sequences: A132388 A132389 A132390 this_sequence A132392 A132393 A132394
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KEYWORD
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nonn,base
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AUTHOR
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Jonathan Vos Post (jvospost3(AT)gmail.com), Aug 29 2007
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