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Search: id:A091290
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| A091290 |
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Solutions x to (q=sigma[x]+sigma[x+1])/sigma[x+x+1], such that q<=1 i.e. sigma[x]+sigma[x+1])<=sigma[2x+1];sigma[]=A000203. |
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+0
5
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| 1, 4, 7, 10, 13, 22, 31, 37, 46, 49, 52, 58, 61, 67, 73, 82, 85, 94, 97, 106, 112, 115, 121, 127, 130, 136, 142, 148, 157, 166, 172, 178, 181, 187, 193, 202, 211, 214, 217, 226, 229, 232, 238, 241, 247, 253, 256, 262, 274, 277, 283, 292, 298, 301, 307, 310, 313
(list; graph; listen)
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OFFSET
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1,2
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MATHEMATICA
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Do[s=(DivisorSigma[1, n]+DivisorSigma[1, n+1])/ DivisorSigma[1, 2*n+1]; If[ !Greater[s, 1], Print[n]], {n, 1, 10000000}]
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CROSSREFS
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Cf. A000203, A091287-A091290.
Sequence in context: A002640 A096675 A069212 this_sequence A119256 A143454 A065810
Adjacent sequences: A091287 A091288 A091289 this_sequence A091291 A091292 A091293
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KEYWORD
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nonn
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AUTHOR
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Labos E. (labos(AT)ana.sote.hu), Feb 16 2004
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