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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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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; refs; listen; history; internal format)
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OFFSET
| 1,1
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LINKS
| Donovan Johnson, Table of n, a(n) for n = 1..300
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PROG
| (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
| Cf. A000396, A000005, A001414.
Sequence in context: A188213 A186052 A186044 * A205648 A059976 A035750
Adjacent sequences: A070308 A070309 A070310 * A070312 A070313 A070314
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KEYWORD
| nonn
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AUTHOR
| Jason Earls (zevi_35711(AT)yahoo.com), May 10 2002
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EXTENSIONS
| More terms from Klaus Brockhaus (klaus-brockhaus(AT)t-online.de), May 15 2002
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