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 A174120 #6 Jun 13 2015 00:53:29
%S A174120 1,2,2,1,1,8,36,115,307,738,1662,3589,7541,15564,31752,64295,129575,
%T A174120 260358,522178,1046105,2094281,4190992,8384812,16772891,33549531,
%U A174120 67103338,134211526,268428525,536863197,1073733268,2147474192
%N A174120 Partial sums of A024012.
%C A174120 A024012 2^n-n^2 -> 1,1,0,-1,0,7,28,79,192,431,924,1927,3952,..
%H A174120 <a href="/index/Rec#order_05">Index entries for linear recurrences with constant coefficients</a>, signature (6,-14,16,-9,2).
%F A174120 a(n) = (-1+2^n-n/6+n^2/2-n^3/3). G.f.: -x*(x^3+4*x^2-4*x+1) / ((x-1)^4*(2*x-1)). - _Colin Barker_, Oct 27 2014
%t A174120 f[n_]:=Sum[2^i-i^2,{i,0,n}];Table[f[n],{n,0,5!}]
%o A174120 (PARI) Vec(-x*(x^3+4*x^2-4*x+1)/((x-1)^4*(2*x-1)) + O(x^100)) \\ _Colin Barker_, Oct 27 2014
%K A174120 nonn,easy
%O A174120 1,2
%A A174120 _Vladimir Joseph Stephan Orlovsky_, Mar 08 2010