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 A173053 #14 Jun 07 2014 20:00:07 %S A173053 0,1,3,118,942,25690,37882 %N A173053 Numbers n such that 2^(2*n)+2*n+1 is a prime. %C A173053 Studying primes of the form 2^(x-1)+x for x=2n+1 leads to A061422. The six odd x in A061422 give the known solutions shown here. [_R. J. Mathar_] %C A173053 The associated primes are 1+1 = 2, 2^2+3 = 7, 2^6+7 = 71, %C A173053 2^236+237 = 110427941548649020598956093796432407239217743554726184882600387580788973; %C A173053 2^1884+1885 = 1382012053...8525348701 (Most inner digits omitted. The number of digits of the prime grows roughly as log_10(4^n) = 0.61*n.) %F A173053 a(n) = floor( A061422(n) / 2). - _Michel Marcus_, Jun 07 2014 %t A173053 Select[Range[0, 2000], PrimeQ[2^(2 #) + 2 # + 1] &] (* _Vincenzo Librandi_, Jun 07 2014 *) %Y A173053 Cf. A061422. %K A173053 nonn,more %O A173053 1,3 %A A173053 _Vincenzo Librandi_, Feb 08 2010 %E A173053 Display of very long primes truncated by _R. J. Mathar_, Feb 15 2010 %E A173053 a(7) from _Vincenzo Librandi_, Jun 07 2014