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 A133609 Numbers n such that n, n+2 and n+4 are consecutive semiprimes. 1
 183, 287, 319, 411, 413, 469, 515, 533, 579, 667, 685, 789, 813, 1055, 1077, 1133, 1145, 1165, 1203, 1253, 1313, 1347, 1383, 1385, 1387, 1389, 1561, 1685, 1687, 1793, 1795, 1817, 1839, 1849, 1919, 1937, 1957, 1959, 2045, 2047, 2155, 2227, 2315, 2317 (list; graph; refs; listen; history; text; internal format)
 OFFSET 1,1 COMMENTS Terms n in A136196 such that n+2 are also in A136196. All terms are odd, so it is a subsequence of A161945. - Michel Marcus, Oct 15 2013 LINKS Charles R Greathouse IV, Table of n, a(n) for n = 1..10000 EXAMPLE 183, 185 and 187 are 59th, 60th and 61st semiprimes, 287, 289 and 291 are 89th, 90th and 91st semiprimes, 319, 321 and 323 are 101st, 102nd and 103rd semiprimes. PROG (PARI) isok(n) = (bigomega(n) == 2) && (bigomega(n+1) != 2) && (bigomega(n+2) == 2) && (bigomega(n+3) != 2) && (bigomega(n+4) == 2); \\ Michel Marcus, Oct 15 2013 CROSSREFS Cf. A136196. Sequence in context: A248628 A217608 A264779 * A305349 A030465 A147270 Adjacent sequences: A133606 A133607 A133608 * A133610 A133611 A133612 KEYWORD nonn AUTHOR Zak Seidov, Dec 28 2007 STATUS approved

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Last modified December 9 18:33 EST 2023. Contains 367693 sequences. (Running on oeis4.)