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 A331720 #4 Jan 31 2020 20:14:31 %S A331720 1,5,23,93,332,1062,3117,8399,21051,49451,109698,231230,465900,901425, %T A331720 1681989,3037536 %N A331720 Number of nonequivalent binary matrices with 4 columns and any number of nonzero rows with n ones in every column up to permutation of rows and columns. %e A331720 The a(1) = 5 matrices are: %e A331720 [1 0 0 0] [1 1 0 0] [1 1 1 0] [1 1 0 0] [1 1 1 1] %e A331720 [0 1 0 0] [0 0 1 0] [0 0 0 1] [0 0 1 1] %e A331720 [0 0 1 0] [0 0 0 1] %e A331720 [0 0 0 1] %Y A331720 Column k=4 of A331461. %K A331720 nonn,more %O A331720 0,2 %A A331720 _Andrew Howroyd_, Jan 31 2020