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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
(list; graph; refs; listen; history; internal format)
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OFFSET
| 1,1
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COMMENTS
| 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
| T. D. Noe, Table of n, a(n) for n=1..1611 (up to 7 digits)
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EXAMPLE
| 144 is a square and so is 441, which is formed by rearranging the digits of 144.
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PROG
| (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
| Sequence in context: A162532 A205190 A085426 * A062917 A035090 A064021
Adjacent sequences: A034286 A034287 A034288 * A034290 A034291 A034292
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KEYWORD
| nonn,base
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AUTHOR
| Erich Friedman (erich.friedman(AT)stetson.edu)
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EXTENSIONS
| Perl program from Jonathan Cross (jcross(AT)juggler.net), Oct 18 2003
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