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 A380630 #11 Mar 02 2025 16:03:55
%S A380630 1,4,144,11250688,50371911404609819639808,
%T A380630 58894902159279477652776826941706227937004584169809397602591562463707136
%N A380630 Number of matrices with n columns, any number of distinct rows and entries in 0..2 and without an all zero row up to permutations of rows and columns.
%C A380630 The matrices can be regarded as sets of n-tuples. Equivalence is up to simultaneous permutations of the tuples.
%C A380630 Another interpretation as the number of non-isomorphic formulas in conjunctive normal form is described in A380610.
%H A380630 Andrew Howroyd, <a href="/A380630/b380630.txt">Table of n, a(n) for n = 0..7</a>
%o A380630 (PARI) \\ Fix, permcount defined in A380610.
%o A380630 a(n)={my(s=0); forpart(q=n, s+=permcount(q)*Fix(q, 1)); s/n!/2}
%Y A380630 Row sums of A380610.
%Y A380630 Cf. A003180, A380518.
%K A380630 nonn
%O A380630 0,2
%A A380630 _Andrew Howroyd_, Feb 19 2025