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Search: id:A083372
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| A083372 |
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Least number having exactly two odd prime factors that differ by 2n. |
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+0
1
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| 15, 21, 55, 33, 39, 85, 51, 57, 115, 69, 203, 145, 87, 93, 259, 185, 111, 205, 123, 129, 235, 141, 371, 265, 159, 413, 295, 177, 183, 469, 335, 201, 355, 213, 219, 553, 395, 237, 415, 249, 623, 445, 267, 1313, 679, 485, 291, 505, 303, 309, 535, 321, 327, 565
(list; graph; listen)
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OFFSET
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1,1
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COMMENT
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The lesser of the two factors is in A002373.
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EXAMPLE
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We have a(4) = 33 because 33 = 3*11, with 11 - 3 = 2*4, the smallest number with this property. Others are 85 = 5*13, 209 = 11*19, 713 = 23*31, 1073 = 29*37, 3233 = 53*61, ...
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MATHEMATICA
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f[n_] := Block[{p = 3}, While[ ! PrimeQ[p] || ! PrimeQ[p + 2n], p++ ]; p(p + 2n)]; Table[ f[n], {n, 1, 55}]
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CROSSREFS
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Cf. A046388.
Sequence in context: A129752 A015831 A063176 this_sequence A119101 A084931 A066758
Adjacent sequences: A083369 A083370 A083371 this_sequence A083373 A083374 A083375
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KEYWORD
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nonn
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AUTHOR
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Lekraj Beedassy (blekraj(AT)yahoo.com), Jun 05 2003
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EXTENSIONS
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Edited and extended by Robert G. Wilson v (rgwv(AT)rgwv.com), Jun 07 2003
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