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 A073141 #12 May 29 2025 20:00:10
%S A073141 0,1,4,9,16,30,30,49,64,108,108,154,108,154,154,225,256,408,408,532,
%T A073141 408,532,532,690,408,532,532,690,532,690,690,961,1024,1584,1584,1960,
%U A073141 1584,1960,1960,2340,1584,1960,1960,2340,1960,2340,2340,2914,1584,1960
%N A073141 Product of the largest and smallest number having in binary representation the same number of 0's and 1's as n.
%C A073141 a(n) = A073137(n) * A073138(n).
%H A073141 Harvey P. Dale, <a href="/A073141/b073141.txt">Table of n, a(n) for n = 0..1000</a>
%H A073141 <a href="/index/Bi#binary">Index entries for sequences related to binary expansion of n</a>
%t A073141 pls[n_]:=With[{d=FromDigits[#,2]&/@Select[Permutations[IntegerDigits[n,2]],#[[1]]==1&]},Max[d]Min[d]]; Join[{0},Array[pls,50]] (* _Harvey P. Dale_, May 29 2025 *)
%Y A073141 Cf. A007088, A073139, A073140.
%K A073141 nonn
%O A073141 0,3
%A A073141 _Reinhard Zumkeller_, Jul 16 2002