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 A177299 #11 May 30 2025 23:16:58 %S A177299 1,1,70,34650,4635540,439192790,51023044582,5712786772130, %T A177299 590059992663400,59838424359107090 %N A177299 Number of permutations of 4 copies of 1..n with all adjacent differences <= 2 in absolute value. %F A177299 a(n) = (4*n)!/24^n for n<=3. %Y A177299 Cf. A014608. %K A177299 nonn,more %O A177299 0,3 %A A177299 _R. H. Hardin_, May 06 2010 %E A177299 a(0), a(9) from _Alois P. Heinz_, May 30 2025