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 A368183 #7 Dec 18 2023 08:28:42
%S A368183 1,1,1,1,2,1,1,0,1,1,1,1,2,1,1,0,2,1,2,1,3,1,1,0,1,0,1,0,1,0,0,0,2,2,
%T A368183 1,1,3,1,1,0,1,1,0,0,1,0,0,0,3,1,1,0,1,0,0,0,1,0,0,0,0,0,0,0,3,2,2,1,
%U A368183 3,1,1,0,2,1,1,0,1,0,0,0,3,1,1,0,1,0,0
%N A368183 Number of sets that can be obtained by choosing a different binary index of each binary index of n.
%C A368183 A binary index of n (row n of A048793) is any position of a 1 in its reversed binary expansion. For example, 18 has reversed binary expansion (0,1,0,0,1) and binary indices {2,5}.
%e A368183 The binary indices of binary indices of 52 are {{1,2},{1,3},{2,3}}, with choices (1,3,2), (2,1,3), both permutations of {1,2,3}, so a(52) = 1.
%t A368183 bpe[n_]:=Join@@Position[Reverse[IntegerDigits[n,2]],1];
%t A368183 Table[Length[Union[Sort/@Select[Tuples[bpe/@bpe[n]],UnsameQ@@#&]]],{n,0,100}]
%Y A368183 For sequences we have A367905, firsts A367910, sorted A367911.
%Y A368183 Positions of zeros are A367907.
%Y A368183 Without distinctness we have A367912, firsts A367913, sorted A367915.
%Y A368183 Positions of positive terms are A367906.
%Y A368183 For sequences without distinctness: A368109, firsts A368111, sorted A368112.
%Y A368183 Positions of first appearances are A368184, sorted A368185.
%Y A368183 A048793 lists binary indices, length A000120, sum A029931.
%Y A368183 A058891 counts set-systems, covering A003465, connected A323818.
%Y A368183 A070939 gives length of binary expansion.
%Y A368183 A096111 gives product of binary indices.
%Y A368183 Cf. A072639, A309326, A326031, A326702, A326753, A355739, A355741, A355744, A367771.
%K A368183 nonn
%O A368183 0,5
%A A368183 _Gus Wiseman_, Dec 17 2023