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 A181233 #6 Jul 22 2025 08:37:47 %S A181233 0,0,20160,57415680,418910083200,9841604944066560, %T A181233 811677284745084979200,246193686664597924471296000, %U A181233 282802656455710907157732271104000,1254507391643066981024665558462201036800 %N A181233 Number of nX(n+3) binary matrices with all rows unique and all columns unique. %F A181233 a(n) = A181230(n,n+3). %Y A181233 Third subdiagonal of A181230. %Y A181233 Cf. A088310, A181231, A181232. %K A181233 nonn %O A181233 1,3 %A A181233 _R. H. Hardin_ Oct 10 2010 %E A181233 More terms from _Max Alekseyev_, Jun 18 2016