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A134600
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Nonprime numbers such that the square mean of their prime factors is an integer (where the square mean of c and d is sqrt((c^2+d^2)/2)).
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23
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1, 4, 8, 9, 16, 25, 27, 32, 49, 64, 81, 119, 121, 125, 128, 161, 169, 243, 256, 289, 343, 351, 361, 378, 455, 512, 527, 529, 595, 625, 721, 729, 841, 845, 918, 959, 961, 1024, 1045, 1081, 1241, 1265, 1323, 1331, 1369, 1375, 1547, 1615, 1681, 1792, 1849, 1855
(list; graph; refs; listen; history; internal format)
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OFFSET
| 1,2
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COMMENTS
| All perfect prime powers (A025475) are included.
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EXAMPLE
| a(5)=25, since 25=5*5 and sqrt((5^2+5^2)/2)=5; a(23)=378, since 378=2*3*3*3*7 and sqrt((2^2+3*3^2+7^2)/5)=sqrt(16)=4.
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CROSSREFS
| Cf. A001597, A025475, A134333, A134344, A134376.
Cf. A134601, A134605, A134608, A134611, A134617, A134619, A134621.
Sequence in context: A087244 A080062 A088949 * A134601 A134611 A134612
Adjacent sequences: A134597 A134598 A134599 * A134601 A134602 A134603
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KEYWORD
| nonn
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AUTHOR
| Hieronymus Fischer (Hieronymus.Fischer(AT)gmx.de), Nov 11 2007
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