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 A278858 #9 Aug 14 2021 07:12:08
%S A278858 1,0,9,240,36864,7741440,3363235524,2203143038208,2248347011420160,
%T A278858 3260265586467690240,6578570637254005920000,
%U A278858 17755898734939822501524480,62673017366111480630785474560,282641923592380319367599892725760,1599753679036773033206787507696238848
%N A278858 a(n) = permanent M_n where M_n is the n X n matrix m(i,j) = abs(i^2-j^2).
%H A278858 Vaclav Kotesovec, <a href="/A278858/b278858.txt">Table of n, a(n) for n = 0..36</a>
%t A278858 Flatten[{1, Table[Permanent[Table[Abs[i^2-j^2], {i, 1, n}, {j, 1, n}]], {n, 1, 15}]}]
%o A278858 (PARI) {a(n) = matpermanent(matrix(n, n, i, j, abs(i^2-j^2)))}
%o A278858 for(n=0, 20, print1(a(n), ", ")) \\ _Vaclav Kotesovec_, Aug 12 2021
%Y A278858 Cf. A085750, A085807, A204249, A278845, A278847, A278857.
%K A278858 nonn
%O A278858 0,3
%A A278858 _Vaclav Kotesovec_, Nov 29 2016