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 A050453 #6 Jun 17 2013 18:36:33
%S A050453 0,0,9,0,0,9,49,0,9,0,121,9,0,49,234,0,0,9,361,0,58,121,529,9,0,0,738,
%T A050453 49,0,234,961,0,130,0,1274,9,0,361,1530,0,0,58,1849,121,234,529,2209,
%U A050453 9,49,0,2610,0,0,738,3146,49,370,0,3481,234,0,961,4027
%N A050453 Sum_{d|n, d=3 mod 4} d^2.
%H A050453 Reinhard Zumkeller, <a href="/A050453/b050453.txt">Table of n, a(n) for n = 1..10000</a>
%o A050453 (Haskell)
%o A050453 a050453 = sum . map (^ 2) . filter ((== 3) . (`mod` 4)) . a027750_row
%o A050453 -- _Reinhard Zumkeller_, Jun 17 2013
%Y A050453 Cf. A027750, A050450.
%K A050453 nonn
%O A050453 1,3
%A A050453 _N. J. A. Sloane_, Dec 23 1999