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
KEYWORD
nonn
AUTHOR
Vladimir Joseph Stephan Orlovsky, Mar 03 2010
STATUS
approved