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 A236553 #17 Feb 07 2014 10:15:30
%S A236553 1,8,14,64,32,112,58,288,110,256,134,896,184,464,448,1056,308,880,382,
%T A236553 2048,812,1072,554,4032,752,1472,974,3712,872,3584,994,4128,1876,2464,
%U A236553 1856,7040,1408,3056,2576,9216,1724,6496,1894,8576,3520,4432,2258,14784,2746
%N A236553 Number of involutions in the quaternion ring over Z/nZ with i^2=j^2=1.
%C A236553 Number of solutions modulo n of the equation system:
%C A236553 a^2 - b^2 + c^2 + d^2 = 1
%C A236553 2ab = 0
%C A236553 2ac = 0
%C A236553 2ad = 0.
%t A236553 invo11[n_] := Length@Reduce[a^2 - b^2 + c^2 + d^2 ==1 && 2 a b== 0 && 2 a c == 0 && 2 a d == 0, Modulus -> n];Table[invo11[n],{n,1,44}]
%Y A236553 Cf. A236554, A227867.
%K A236553 nonn,mult
%O A236553 1,2
%A A236553 _José María Grau Ribas_, Jan 28 2014