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 A062155 #9 Feb 03 2021 20:09:27
%S A062155 1,3,38,1107,58938,5002470,620355870,105848185590,23785613520480,
%T A062155 6809213491925040,2419333087316808600,1044664066287091958400,
%U A062155 538796052743780959419600,327150260492074733413299600,230994366606893955257329737600,187668642106165851767306588418000
%N A062155 Number of n-row matrices over {0,1,2} with all row and column sums equal to 1 or 2.
%D A062155 I. P. Goulden and D. M. Jackson, Combinatorial Enumeration, Wiley, N.Y., 1983,(Problem 3.4.15).
%H A062155 Andrew Howroyd, <a href="/A062155/b062155.txt">Table of n, a(n) for n = 0..100</a>
%e A062155 There are 38 2-row matrices over {0,1,2} with all row and column sums equal to 1 or 2: 1 of type 2 X 1, 13 of type 2 X 2, 18 of type 2 X 3 and 6 of type 2 X 4, cf. A062154.
%o A062155 (PARI) seq(n)={[subst(serlaplace(p),y,1) | p <- Vec(serlaplace(1/sqrt(1-x*y + O(x*x^n))*exp(x*y/2+1/(1-x*y)*(x*y+x^2*y/2+x*y^2/2) + O(x*x^n))))]} \\ _Andrew Howroyd_, Feb 03 2021
%Y A062155 Row sums of A062154.
%Y A062155 Cf. A062156.
%K A062155 easy,nonn
%O A062155 0,2
%A A062155 _Vladeta Jovovic_, Jun 06 2001
%E A062155 Terms a(14) and beyond from _Andrew Howroyd_, Feb 03 2021