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 A173966 Sums of two consecutive semiprimes. 4
 19, 29, 43, 51, 67, 69, 77, 115, 171, 173, 187, 189, 237, 243, 245, 267, 283, 285, 291, 317, 355, 403, 405, 411, 427, 429, 435, 437, 507, 597, 603, 605, 653, 669, 723, 763, 787, 789, 891, 893, 907, 963, 1003, 1029, 1053, 1075, 1085, 1107, 1131, 1245, 1267 (list; graph; refs; listen; history; text; internal format)
 OFFSET 1,1 COMMENTS First 16 terms:19,29,43,51,67,69,77,115,171,173,187,189,237,243,245,267 are the same as in A157483. These are sums of two consecutive integers which are both semiprimes, whereas A118717 are sums of two semiprimes which are adjacent (consecutive) in A001358. [From R. J. Mathar, Mar 18 2010] LINKS Harvey P. Dale, Table of n, a(n) for n = 1..1000 MATHEMATICA f[n_]:=Last/@FactorInteger[n]=={1, 1}||Last/@FactorInteger[n]=={2}; lst={}; Do[If[f[n], If[f[n+1], AppendTo[lst, 2*n+1]]], {n, 7!}]; lst Total/@Select[Partition[Select[Range[700], PrimeOmega[#]==2&], 2, 1], #[[2]]- #[[1]] == 1&] (* Harvey P. Dale, Jun 22 2020 *) CROSSREFS Sequence in context: A276049 A108183 A157483 * A096218 A100590 A046120 Adjacent sequences:  A173963 A173964 A173965 * A173967 A173968 A173969 KEYWORD nonn AUTHOR Vladimir Joseph Stephan Orlovsky, Mar 03 2010 STATUS approved

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Last modified October 25 17:50 EDT 2020. Contains 338012 sequences. (Running on oeis4.)