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 A083372 Least number having exactly two odd prime factors that differ by 2n. 0
 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; refs; listen; history; text; internal format)
 OFFSET 1,1 COMMENTS The lesser of the two factors is in A002373. LINKS EXAMPLE 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, ... MATHEMATICA f[n_] := Block[{p = 3}, While[ ! PrimeQ[p] || ! PrimeQ[p + 2n], p++ ]; p(p + 2n)]; Table[ f[n], {n, 1, 55}] Table[#(#+2n)&/@Select[Prime[Range[2, 100]], PrimeQ[#+2n]&, 1], {n, 60}]// Flatten (* Harvey P. Dale, May 26 2018 *) CROSSREFS Cf. A046388. Sequence in context: A015831 A275169 A063176 * A119101 A342806 A190662 Adjacent sequences:  A083369 A083370 A083371 * A083373 A083374 A083375 KEYWORD nonn AUTHOR Lekraj Beedassy, Jun 05 2003 EXTENSIONS Edited and extended by Robert G. Wilson v, Jun 07 2003 STATUS approved

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Last modified May 25 05:58 EDT 2022. Contains 354048 sequences. (Running on oeis4.)