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 A184286 #17 Nov 01 2017 12:23:24
%S A184286 45,2635,217125,20346485,2034505661,211927741375,22706531350485,
%T A184286 2483526875847735,275947429516276125,31044085821533856483,
%U A184286 3527737025058633700325,404219867454740790585125,46640753937073243032602205,5413658939124584198288696455
%N A184286 Number of distinct n X 3 toroidal 0..4 arrays.
%H A184286 Andrew Howroyd, <a href="/A184286/b184286.txt">Table of n, a(n) for n = 1..100</a>
%t A184286 T[n_, k_] := (1/(n*k))*Sum[Sum[EulerPhi[c]*EulerPhi[d]*5^(n*k/LCM[c, d]), {d, Divisors[k]}], {c, Divisors[n]}]; a[n_] := T[n, 3]; Array[a, 14] (* _Jean-François Alcover_, Nov 01 2017, after _Andrew Howroyd_ *)
%o A184286 (PARI) a(n) = my(k=3); (1/(n*k)) * sumdiv(n, c, sumdiv(k, d, eulerphi(c) * eulerphi(d) * 5^(n*k/lcm(c, d)))); \\ _Michel Marcus_, Nov 01 2017
%Y A184286 Column 3 of A184288.
%K A184286 nonn
%O A184286 1,1
%A A184286 _R. H. Hardin_, Jan 10 2011
%E A184286 Terms a(8) and beyond from _Andrew Howroyd_, Sep 27 2017