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 A204558 #9 Apr 02 2013 13:14:07 %S A204558 1,6,45,120,325,630,1225,2016,3321,4950,7381,10296,14365,19110,25425, %T A204558 32640,41905,52326,65341,79800,97461,116886,140185,165600,195625, %U A204558 228150,266085,306936,354061,404550,462241,523776,593505,667590,750925,839160,937765 %N A204558 Row sums of the triangle A045975. %C A204558 a(n) = sum(A045975(n,k): k = 1 .. n); %C A204558 a(n) = n * (if n even then A035328(n/2) else A005817((n+1)/2)). [_Reinhard Zumkeller_, Jan 18 2012] %F A204558 Conjecture: a(n) = (n^2*(-(-1)^n+n^2))/2. G.f.: -x*(x^6 +4*x^5 +31*x^4 +24*x^3 +31*x^2 +4*x +1) / ((x -1)^5*(x +1)^3). - _Colin Barker_, Apr 02 2013 %o A204558 (Haskell) %o A204558 a204558 = sum . a045975_row %K A204558 nonn %O A204558 1,2 %A A204558 _Reinhard Zumkeller_, Jan 18 2012