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 A177298 #18 May 16 2020 01:33:32 %S A177298 1,1,70,780,11482,135040,1543862,16699380,175280570,1792874048, %T A177298 17990831182,177773616180,1735220375914,16769137076968, %U A177298 160740670148270,1530462874512756,14491157235576770,136575590461035368,1282229192334549022,11999276440029403356,111987255233226452770 %N A177298 Number of permutations of 4 copies of 1..n with all adjacent differences <= 1 in absolute value. %C A177298 a(n) = (4n)!/24^n = A014608(n) for n<=2. %H A177298 Andrew Howroyd, <a href="/A177298/b177298.txt">Table of n, a(n) for n = 0..200</a> %Y A177298 Cf. A014608. %Y A177298 Column k=4 of A331562. %K A177298 nonn %O A177298 0,3 %A A177298 _R. H. Hardin_, May 06 2010 %E A177298 a(0)=1 prepended by _Alois P. Heinz_, Jan 20 2020 %E A177298 a(12)-a(13) from _Alois P. Heinz_, Jan 21 2020 %E A177298 Terms a(14) and beyond from _Andrew Howroyd_, May 15 2020