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 A204234 #9 Nov 14 2016 13:56:57
%S A204234 1,2,25,1018,97617,18239786,5881589105,3009156161810,2296768410595849,
%T A204234 2494959953768765810,3716590842220109346457,7367123790912343973015562,
%U A204234 18955419073428722394855382209,61999496577719659890376379418138,253245883804141341597229595842097313
%N A204234 Permanent of the n-th principal submatrix of A203990.
%p A204234 with(LinearAlgebra):
%p A204234 a:= n-> `if`(n=0, 1, Permanent(Matrix(n, (i, j)-> (i+j)*min(i, j)))):
%p A204234 seq(a(n), n=0..16); # _Alois P. Heinz_, Nov 14 2016
%t A204234 f[i_, j_] := (i + j) Min[i, j]; (* A203990 *)
%t A204234 m[n_] := Table[f[i, j], {i, 1, n}, {j, 1, n}]
%t A204234 Table[Det[m[n]], {n, 1, 22}] (* A114160 *)
%t A204234 Permanent[m_] :=
%t A204234 With[{a = Array[x, Length[m]]},
%t A204234 Coefficient[Times @@ (m.a), Times @@ a]];
%t A204234 Table[Permanent[m[n]], {n, 1, 14}] (* A204234 *)
%Y A204234 Cf. A203990.
%K A204234 nonn
%O A204234 0,2
%A A204234 _Clark Kimberling_, Jan 13 2012
%E A204234 a(0)=1 prepended and one more term added by _Alois P. Heinz_, Nov 14 2016