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A034289
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Squares which can be rearranged into squares with the same number of digits.
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4
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144, 169, 196, 256, 441, 625, 961, 1024, 1089, 1296, 1369, 1764, 1936, 2401, 2916, 4096, 4761, 9216, 9604, 9801, 10201, 10404, 10609, 11236, 11664, 12100, 12544, 12769, 14400, 14884, 16384, 16641, 16900, 17689, 18225, 18769, 19600, 20736
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OFFSET
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1,1
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COMMENTS
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Squares that have some nontrivial permutation of digits which are also squares.
There are 87 10-digit squares whose digits are a permutation of the digits 0..9. - T. D. Noe, Jan 23 2008
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LINKS
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Gaurav Kumar, Table of n, a(n) for n = 1..523877 [This replaces an earlier b-file computed by T. D. Noe]
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EXAMPLE
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144 is a square and so is 441, which is formed by rearranging the digits of 144.
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PROG
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(Perl)
#!/usr/bin/perl
# change this to compute more terms:
$max_digits = 5;
# put the squares into a hash table; for example
# 46 -> 64
# 144 -> 144 441
# 169 -> 169 196 961
$max_i = sqrt(10 ** $max_digits);
for $i (1..$max_i)
{
$i_sq = $i * $i;
$normalized = join('', sort(split(//, "$i_sq")));
$sq_hash{"$normalized"} .= "$i_sq ";
}
# find the hash entries with more than one square
foreach (values(%sq_hash)) { $nums .= $_ if (/ \d/); }
# print the numbers in order
print join(' ', sort( { $a <=> $b } split(' ', "$nums")));
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CROSSREFS
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Sequence in context: A162532 A205190 A085426 * A062917 A035090 A064021
Adjacent sequences: A034286 A034287 A034288 * A034290 A034291 A034292
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KEYWORD
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nonn,base
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AUTHOR
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Erich Friedman
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EXTENSIONS
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Perl program from Jonathan Cross (jcross(AT)juggler.net), Oct 18 2003
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STATUS
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approved
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