This is a front-end for the Online Encyclopedia of Integer Sequences, made by Christian Perfect. The idea is to provide OEIS entries in non-ancient HTML, and then to think about how they're presented visually. The source code is on GitHub.
%I A176071 #17 Jul 11 2023 17:49:37
%S A176071 21,38,265,4109,65553,262163,1048597,67108891,274877906983,
%T A176071 4503599627370549,73786976294838206531,75557863725914323419213,
%U A176071 302231454903657293676623,5192296858534827628530496329220209,10889035741470030830827987437816582766726,95780971304118053647396689196894323976171195136475313
%N A176071 Numbers of the form 2^k + k + 1 that are the product of two distinct primes.
%e A176071 21 = 3 * 7 = 2^4 + 4 + 1
%t A176071 f[n_]:=Last/@FactorInteger[n]=={1,1};Select[Array[2^#+#+1&,140,0],f[ # ]&]
%t A176071 Select[Table[2^k+k+1,{k,0,200}],PrimeNu[#]==PrimeOmega[#]==2&] (* _Harvey P. Dale_, Jul 11 2023 *)
%o A176071 (PARI) is(n) = my(f = factor(n), e = logint(n, 2)); f[,2] == [1, 1]~ && n == 1<<e + e + 1 \\ _David A. Corneth_, May 27 2023
%Y A176071 Cf. A005126, A053698, A061421, A174969, A176069, A176070.
%K A176071 nonn
%O A176071 1,1
%A A176071 _Vladimir Joseph Stephan Orlovsky_, Apr 07 2010
%E A176071 Name corrected by _David A. Corneth_, May 27 2023