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 A030110 #18 Jan 16 2017 03:24:09 %S A030110 2,2,1,0,1,8,29,80,193,432,925,1928,3953,8024,16189,32544,65281, %T A030110 130784,261821,523928,1048177,2096712,4193821,8388080,16776641, %U A030110 33553808,67108189,134217000,268434673,536870072,1073740925,2147482688 %N A030110 a(n) = 2^n - n^2 + 1. %H A030110 Matthew House, <a href="/A030110/b030110.txt">Table of n, a(n) for n = 0..3305</a> %H A030110 <a href="/index/Rec#order_04">Index entries for linear recurrences with constant coefficients</a>, signature (5,-9,7,-2). %F A030110 G.f.: (2-8*x+9*x^2-x^3)/((1-2*x)*(1-x)^3). %F A030110 a(n) = 5*a(n-1) - 9*a(n-2) + 7*a(n-3) - 2*a(n-4). - _Matthew House_, Jan 15 2017 %p A030110 A030110:=n->2^n-n^2+1: seq(A030110(n), n=0..50); # _Wesley Ivan Hurt_, Jan 15 2017 %t A030110 f[n_]:=2^n-n^2+1;f[Range[0,100]] (* _Vladimir Joseph Stephan Orlovsky_, Feb 19 2011 *) %K A030110 nonn,easy %O A030110 0,1 %A A030110 Steve Gray (stevebg(AT)roadrunner.com)