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 A264046 Numbers k such that k and k+6 are consecutive semiprimes. 2
 15, 123, 365, 371, 505, 545, 573, 591, 649, 707, 807, 843, 943, 1067, 1159, 1247, 1357, 1405, 1529, 1555, 1633, 1739, 1745, 1829, 1843, 1897, 1909, 1985, 2149, 2159, 2209, 2285, 2329, 2353, 2363, 2407, 2413, 2463, 2501, 2643, 2773, 2779 (list; graph; refs; listen; history; text; internal format)
 OFFSET 1,1 COMMENTS Note that a(1) = 15 = A131109(k=6). LINKS Charles R Greathouse IV, Table of n, a(n) for n = 1..10000 EXAMPLE 15 = A001358(6) and 21 = A001358(7). PROG (PARI) is(n)=if(bigomega(n)!=2 || bigomega(n+6)!=2, return(0)); for(i=1, 5, if(bigomega(n+i)==2, return(0))); 1 \\ Charles R Greathouse IV, Nov 02 2015 CROSSREFS Cf. A001358, A065516, A123375, A131109, A136196, A264043, A264044, A264045. Sequence in context: A264377 A038743 A181377 * A349295 A027839 A034271 Adjacent sequences: A264043 A264044 A264045 * A264047 A264048 A264049 KEYWORD nonn AUTHOR Zak Seidov, Nov 02 2015 STATUS approved

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Last modified December 3 05:03 EST 2023. Contains 367531 sequences. (Running on oeis4.)