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Search: id:A070311
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| A070311 |
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Numbers n such that sopfr(n) and d(n) are both perfect numbers. |
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+0
1
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| 338, 2496, 3520, 153280, 508096, 678592, 1162432, 1461952, 2130112, 2475712, 2595520, 2959552, 3042496, 3388096, 3443392, 3581632, 3733696, 3742912, 3744873, 5713173, 9492309, 11912896, 14767353, 15009472, 18021609, 21703125
(list; graph; listen)
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OFFSET
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1,1
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PROGRAM
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(PARI) {for(n=1, 22000000, d=numdiv(n); if(d==sigma(d)-d, s=0; F=factor(n); for(i=1, matsize(F)[1], s=s+F[i, 1]*F[i, 2]); if(s==sigma(s)-s, print1(n, ", "))))}
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CROSSREFS
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Cf. A000396, A000005, A001414.
Sequence in context: A084231 A066478 A031128 this_sequence A059976 A035750 A107546
Adjacent sequences: A070308 A070309 A070310 this_sequence A070312 A070313 A070314
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KEYWORD
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nonn
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AUTHOR
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Jason Earls (zevi_35711(AT)yahoo.com), May 10 2002
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EXTENSIONS
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More terms from Klaus Brockhaus (klaus-brockhaus(AT)t-online.de), May 15 2002
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