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 A099440 #11 Aug 01 2023 15:32:35
%S A099440 11,1013,16369,65519,67108837,1125899906842573,72057594037927879,
%T A099440 1180591620717411303353,83076749736557242056487941267521419
%N A099440 Primes of the form A000295(k) = 2^k - k - 1.
%C A099440 The next term a(10) = 2^2072-2073 has 624 decimal digits.
%C A099440 a(11) has 1882 decimal digits. - _Vincenzo Librandi_, Jul 18 2012
%H A099440 Vincenzo Librandi, <a href="/A099440/b099440.txt">Table of n, a(n) for n = 1..10</a>
%e A099440 a(2) = 1013 because A000295(A099439(2)) = 2^10 - 10 - 1 is prime.
%t A099440 Select[Table[2^n-n-1,{n,0,7000}],PrimeQ] (* _Vincenzo Librandi_, Jul 18 2012 *)
%o A099440 (Magma) [ a: n in [1..200] | IsPrime(a) where a is 2^n-n-1 ]; // _Vincenzo Librandi_, Jul 18 2012
%Y A099440 Cf. A000295 2^n-n-1 (column 2 of the Eulerian numbers), A099439 2^n-n-1 is prime, A099441 2^n-n-1 is a semiprime, A099442 semiprimes in A000295.
%K A099440 nonn
%O A099440 1,1
%A A099440 _Hugo Pfoertner_, Oct 18 2004