cp's OEIS Frontend

A085745 Numbers m such that 2^m + m is a semiprime.

%I A085745 #27 Oct 26 2024 10:45:48
%S A085745 2,11,23,34,59,69,87,95,119,123,129,171,197,239,341,425,455,471,515,
%T A085745 519,635,765,959,1115,1181,1210
%N A085745 Numbers m such that 2^m + m is a semiprime.
%C A085745 a(27) >= 1239. If 1239 is not a term then a(27) = 1275. - _Amiram Eldar_, Oct 26 2024
%H A085745 factordb, <a href="https://factordb.com/index.php?query=2%5E1239%2B1239&amp;use=n&amp;n=1210&amp;VP=on&amp;VC=on&amp;EV=on&amp;OD=on&amp;PR=on&amp;PRP=on&amp;U=on&amp;C=on&amp;perpage=200&amp;format=3">2^1239+1239</a>.
%F A085745 a(n) = 2*k <=> A089535(n) is even <=> A089536(n) = 2 <=> A089537(n) = 4^k/2 + k, and for any prime of this form, there is a term a(n) = 2*k in this sequence. - _M. F. Hasler_, Oct 08 2009
%t A085745 Select[Range[1300],PrimeOmega[2^#+#]==2&] (* _Harvey P. Dale_, Dec 18 2014 *)
%Y A085745 Cf. A006127, A052007, A089535, A089536, A089537.
%Y A085745 Sequences A165767, A165768, A165769 are the analog for 2^n-n. - _M. F. Hasler_, Oct 08 2009
%K A085745 nonn,more
%O A085745 1,1
%A A085745 _Jason Earls_, Jul 21 2003
%E A085745 More terms from _Ray Chandler_, Nov 08 2003
%E A085745 a(15) from _Donovan Johnson_, Mar 06 2008
%E A085745 a(16)-a(26) from _Sean A. Irvine_, Oct 27 2009
%E A085745 Offset changed to 1 by _Jinyuan Wang_, Jul 30 2021