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 A226236 #41 Dec 16 2016 03:06:43
%S A226236 1,3,105,11025,5439105,11193473025,89273960290305,2926331900465537025,
%T A226236 380704455834655419367425,200503685263248842050957082625,
%U A226236 418936006416927720918846481798529025,3516831926000321799217446305276779638554625
%N A226236 Number of semisimple invertible n X n matrices over GF(2).
%C A226236 Fulman shows that the ratio a(n)/A002884(n) converges to Product_{r>=1, r == 0,2,3 mod 5} (1-2^(-(r-1)))/(1-2^(-r)).
%H A226236 Jason Fulman, <a href="http://arxiv.org/abs/math/9712239">Cycle Indices for the Finite Classical Groups</a>, J. Group Thy., v. 2, 1999, 251-289.
%e A226236 a(2) = 3, the matrices are [[1,0],[0,1]], [[0,1],[1,1]], [[1,1],[1,0]].
%Y A226236 Cf. A225371 (every semisimple matrix over GF(2) is a square of another matrix).
%K A226236 nonn,nice
%O A226236 1,2
%A A226236 _Victor S. Miller_, Jun 04 2013