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 A363121 #19 May 18 2023 10:40:27
%S A363121 1,12,40,56,144,176,208,240,544,608,672,736,800,864,928,992,2112,2240,
%T A363121 2368,2496,2624,2752,2880,3008,3136,3264,3392,3520,3648,3776,3904,
%U A363121 4032,8320,8576,8832,9088,9344,9600,9856,10112,10368,10624,10880,11136,11392,11648,11904
%N A363121 Primitive terms of A116882: terms k of A116882 such that k/2 is not a term of A116882.
%C A363121 If k is a term of this sequence then k*2^m is a term of A116882 for any m >= 0.
%H A363121 Amiram Eldar, <a href="/A363121/b363121.txt">Table of n, a(n) for n = 1..10000</a>
%F A363121 a(n) = (2*n-1)*2^A070941(n-1), for n > 1.
%t A363121 q[n_] := 2^(2*IntegerExponent[n, 2]) >= n; Join[{1}, Select[Range[2, 12000, 2], q[#] && !q[#/2] &]]
%t A363121 (* or *)
%t A363121 a[1] = 1; a[n_] := (2*n - 1)*2^IntegerLength[2*n - 1, 2]; Array[a, 100]
%o A363121 (PARI) a(n) = if(n == 1, 1, (2*n - 1)*2^length(binary(2*n - 1)));
%o A363121 (Python)
%o A363121 def A363121(n): return (m:=2*n-1)<<m.bit_length() if n>1 else 1 # _Chai Wah Wu_, May 17 2023
%Y A363121 Cf. A070941, A116882.
%K A363121 nonn,easy
%O A363121 1,2
%A A363121 _Amiram Eldar_, May 16 2023