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 A068472 #7 Sep 26 2024 18:52:05 %S A068472 1,2,16,496,58640,26536192,45851039232,302758305892480, %T A068472 7638804476736307712,736437724731312162567680, %U A068472 271287639195997221896855543808,381862430868672544566361613406502912 %N A068472 Number of n X n binary matrices with every 1 having at most 3 adjacent 1's. %Y A068472 No adjacent 1's A006506, one adjacent 1 A067968. %K A068472 nonn %O A068472 0,2 %A A068472 _R. H. Hardin_, Mar 10 2002 %E A068472 a(0)=1 prepended by _Alois P. Heinz_, Sep 26 2024