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Search: id:A070224
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| A070224 |
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Numbers n such that the sum of p^2, where p are the prime divisors of n, divides the sum of d^2, where d are the divisors of n. |
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1
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| 18, 36, 72, 96, 140, 144, 234, 288, 336, 468, 486, 490, 576, 825, 864, 924, 936, 972, 980, 1008, 1120, 1152, 1248, 1872, 1944, 1960, 2300, 2304, 2310, 2352, 2592, 2673, 2772, 2964, 3024, 3040, 3234, 3332, 3500, 3610, 3744, 3840, 3888, 3920, 4235, 4329
(list; graph; listen)
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OFFSET
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1,1
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EXAMPLE
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The sum of square divisors of 2352 is sigma_2(2352)=8357910; prime divisors of 2352 are 2,3,7 and (8357910)/(2^2+3^2+7^2)=8357910/62=134805 hence 2352 is in the sequence.
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PROGRAM
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(PARI) for(n=2, 10000, if(sumdiv(n, d, d^2)%sumdiv(n, d, isprime(d)*d^2)==0, print1(n, ", ")))
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CROSSREFS
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Sequence in context: A011799 A097926 A087967 this_sequence A083211 A156903 A023149
Adjacent sequences: A070221 A070222 A070223 this_sequence A070225 A070226 A070227
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KEYWORD
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easy,nonn
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AUTHOR
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Benoit Cloitre (benoit7848c(AT)orange.fr), May 07 2002
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