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 A091061 #17 May 02 2022 18:43:53
%S A091061 1,1,9,408,332034,3327329224,382430372929443,521184164586987473279,
%T A091061 8728898357751671813141271503,1850296785573740600565249566845514268,
%U A091061 5085095493754879591102840109774321148107411672,184819445887199812520846920949561110945504502827686252918
%N A091061 Number of n X n matrices over symbol set {1,2,3,4} equivalent under any permutation of row, columns or the symbol set.
%H A091061 C. G. Bower, <a href="/A091057/a091057.html">Explanation of A091057-A091062</a>
%H A091061 <a href="/index/Mat#inequiv">Index to number of inequivalent matrices modulo permutation of rows and columns</a>
%F A091061 a(n) = sum_{1*s_1+2*s_2+...=n, 1*t_1+2*t_2+...=n, 1*u_1+2*u_2+...=4} (fixA[s_1, s_2, ...;t_1, t_2, ...;u_1, u_2, ...]/(1^s_1*s_1!*2^s_2*s_2!* ... *1^t_1*t_1!*2^t_2*t_2!* ... *1^u_1*u_1!*2^u_2*u_2!*...)) where fixA[...] = prod_{i, j>=1} ( (sum_{d|lcm(i, j)} (d*u_d))^(gcd(i, j)*s_i*t_j)).
%Y A091061 Cf. A091057-A091062.
%Y A091061 Column k=4 of A242095.
%K A091061 nonn
%O A091061 0,3
%A A091061 _Christian G. Bower_, Dec 17 2003
%E A091061 a(11) from _Alois P. Heinz_, Aug 14 2014