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 A086647 #13 Mar 29 2019 09:58:23
%S A086647 1,2,4,12,36,128,460,1750,6551,25108,94977,363533,1378573,5273561
%N A086647 Number of monomials in expansion of permanent of an n X n Toeplitz matrix [t(|i-j|) ] in terms of its entries.
%p A086647 with(LinearAlgebra): f:=n->nops([coeffs(Permanent(Matrix(n, (i, j) -> a[abs(i-j)])))]): [seq(f(n), n=1..12)]; # _Vaclav Kotesovec_, Mar 29 2019
%t A086647 Permanent[m_List] := With[{v = Array[x, Length@m]}, Coefficient[Times @@ (m . v), Times @@ v]]; ; f[n_] := Length@Expand@Permanent@Table[t[Abs[i - j]], {i, n}, {j, n}]; Array[f, 11] (* _Robert G. Wilson v_ *)
%Y A086647 Cf. A019447, A019448, A019589.
%K A086647 nonn
%O A086647 1,2
%A A086647 Yuval Dekel (dekelyuval(AT)hotmail.com), Jul 26 2003
%E A086647 More terms from _Robert G. Wilson v_, Sep 22 2006
%E A086647 a(12) from _Vaclav Kotesovec_, Mar 20 2019
%E A086647 a(13)-a(14) from _Vaclav Kotesovec_, Mar 29 2019