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 A331344 #8 Jan 16 2020 01:12:53 %S A331344 1,2,15,317,12586,803764,75603729,9880078404,1719511013708, %T A331344 385900586669488,108870763685147631,37821200661333033093, %U A331344 15903952714275755480410,7978911737260660423782839,4717171385049289138016854041,3251403192784472823846341645000 %N A331344 Number of nonnegative integer matrices with n distinct columns and any number of distinct nonzero rows with each column sum being 3 and rows in decreasing lexicographic order. %C A331344 The condition that the rows be in decreasing order is equivalent to considering nonequivalent matrices with distinct rows up to permutation of rows. %H A331344 Andrew Howroyd, <a href="/A331344/b331344.txt">Table of n, a(n) for n = 0..100</a> %Y A331344 Row n=3 of A331160. %Y A331344 Cf. A331196, A331316, %K A331344 nonn %O A331344 0,2 %A A331344 _Andrew Howroyd_, Jan 14 2020