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 A363351 #11 Nov 19 2023 15:56:56
%S A363351 1,1,4,15,276,11781,1878976,1025425687,1991615557152,
%T A363351 13956142211859705,356420795746828010496,33403125520521519582574755,
%U A363351 11550847036800645994553295682560,14809214844165378046279886451931058885,70706990798105074752791720424861516970573824
%N A363351 Number of n element multisets of length n vectors over GF(2) that sum to zero.
%C A363351 Number of equivalence classes of n X n binary matrices with an even number of 1's in each column under permutation of rows.
%C A363351 Number of equivalence classes of n X n binary matrices under permutation of rows and complementation of columns.
%H A363351 Andrew Howroyd, <a href="/A363351/b363351.txt">Table of n, a(n) for n = 0..50</a>
%F A363351 a(n) = binomial(2^n+n-1, n)/2^n for odd n;
%F A363351 a(n) = (binomial(2^n+n-1, n) + (2^n-1)*binomial(2^(n-1)+n/2-1, n/2))/2^n for even n.
%t A363351 A363351[n_]:=(Binomial[2^n+n-1,n]+If[EvenQ[n],(2^n-1)Binomial[2^(n-1)+n/2-1,n/2],0])/2^n;Array[A363351,20,0] (* _Paolo Xausa_, Nov 19 2023 *)
%o A363351 (PARI) a(n)={(binomial(2^n+n-1, n) + if(n%2==0, (2^n-1)*binomial(2^(n-1)+n/2-1, n/2)))/2^n}
%Y A363351 Main diagonal of A362905.
%Y A363351 Cf. A006383.
%K A363351 nonn
%O A363351 0,3
%A A363351 _Andrew Howroyd_, May 30 2023