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 A090013 #14 Feb 20 2024 13:17:25
%S A090013 4,16,84,536,4004,34176,327604,3481096,40585284,514872176,7058605844,
%T A090013 103969203576,1637182717924,27442553929696,487806792137844,
%U A090013 9164718013496936,181446744138509444,3775570370986139856
%N A090013 Permanent of (0,1)-matrix of size n X (n+d) with d=3 and n-1 zeros not on a line.
%D A090013 Brualdi, Richard A. and Ryser, Herbert J., Combinatorial Matrix Theory, Cambridge NY (1991), Chapter 7.
%H A090013 Indranil Ghosh, <a href="/A090013/b090013.txt">Table of n, a(n) for n = 1..446</a>
%H A090013 Seok-Zun Song et al., <a href="https://doi.org/10.1016/S0024-3795(03)00382-3">Extremes of permanents of (0,1)-matrices</a>, Lin. Algebra and its Applic. 373 (2003), pp. 197-210.
%F A090013 a(n) = (n+2)*a(n-1) + (n-2)*a(n-2), a(1)=4, a(2)=16
%F A090013 a(n) ~ exp(-1) * n! * n^3 / 6. - _Vaclav Kotesovec_, Nov 30 2017
%t A090013 t={4,16};Do[AppendTo[t,(n+2)*t[[-1]]+(n-2)*t[[-2]]],{n,3,18}];t (* _Indranil Ghosh_, Feb 21 2017 *)
%Y A090013 a(n) = A000261(n-1) + A000261(n), a(1)=4
%Y A090013 Cf. A000255, A000153, A000261, A001909, A001910, A090010, A055790, A090012-A090016.
%K A090013 nonn,easy
%O A090013 1,1
%A A090013 _Jaap Spies_, Dec 13 2003
%E A090013 Corrected by _Jaap Spies_, Jan 26 2004