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 A089481 #7 Feb 20 2024 13:16:57 %S A089481 9,0,1,265,0,63,0,9,0,1,27713,0,9360,0,3582,0,1248,0,648,0,288,0,48,0, %T A089481 72,0,0,0,16,0,0,0,0,0,1,10363361,0,3645600,0,2411250,0,1404800,0, %U A089481 1043700,0,682200,0,417100,0,336600,0,177750,0,183400,0,85950,0,60000,0 %N A089481 Triangle T(n,k) read by rows, where T(n,k) = number of times the permanent of a real singular n X n (0,1)-matrix takes the value k, for n >= 2, 0 <= k <= n!. %H A089481 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 A089481 T(n, n!) = 1. %Y A089481 T(n, 0)=A088672(n). The n-th row of the table contains A089476(n) nonzero entries. Cf. A089479 occurrence counts for permanents of all (0, 1)-matrices. %K A089481 nonn,tabf %O A089481 2,1 %A A089481 _Hugo Pfoertner_, Nov 09 2003