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 A210251 #11 Jul 27 2017 13:29:42
%S A210251 1,9,21,25,29,41,49,61,69,81,89
%N A210251 Residues modulo 100 of odd squares.
%F A210251 {1,9} + {0,1,2,3,4}*20 union {25}.
%t A210251 Mod[#,100]&/@(Range[1,55,2]^2)//Union (* _Harvey P. Dale_, Jul 27 2017 *)
%o A210251 (PARI) vecsort(vector(12,n,(2*n-1)^2)%100,,8)
%Y A210251 Range of A016754. Odd terms from A010461. See also A002015, A008959, A174452.
%Y A210251 Also the range of A030156 and A192775 without initial term.
%K A210251 nonn,base,fini,full
%O A210251 1,2
%A A210251 _M. F. Hasler_, Mar 19 2012