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 A127963 #21 Jul 23 2023 06:06:08
%S A127963 2,3,4,6,7,9,10,12,16,22,31,40,51,64,84,96,100,157,174,351,855,1309,
%T A127963 1770,2904,5251,5346,5640,6196,7240,21369,41670,47685,58620,63516,
%U A127963 69469,70540,133509,134994,187161,493096,2015700
%N A127963 Number of 1's in A127962(n).
%F A127963 a(n) = A000120(A000979(n)). - _Michel Marcus_, Nov 07 2013
%F A127963 a(n) = A007953(A127962(n)). - _Amiram Eldar_, Jul 23 2023
%t A127963 b = {}; Do[c = 1 + Sum[2^(2n - 1), {n, 1, x}]; If[PrimeQ[c], AppendTo[b, c]], {x, 0, 1000}]; a = {}; Do[AppendTo[a, FromDigits[IntegerDigits[b[[x]], 2]]], {x, 1, Length[b]}]; d = {}; Do[AppendTo[d, DigitCount[a[[x]], 10, 1]], {x, 1, Length[a]}]; d (* _Artur Jasinski_, Feb 09 2007 *)
%t A127963 DigitCount[#, 2, 1]& /@ Select[Table[(2^p + 1)/3, {p, Prime[Range[300]]}], PrimeQ] (* _Amiram Eldar_, Jul 23 2023 *)
%Y A127963 Cf. A000120, A000978, A000979, A007953, A124400, A126614, A127936, A127955, A127956, A127957, A127958, A127961, A127962.
%K A127963 nonn,base,more
%O A127963 1,1
%A A127963 _Artur Jasinski_, Feb 09 2007
%E A127963 a(22)-a(29) from _Vincenzo Librandi_, Mar 31 2012
%E A127963 a(30)-a(41) from _Amiram Eldar_, Jul 23 2023