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 A036404 #15 Jul 08 2025 21:44:28 %S A036404 0,1,1,2,4,5,8,10,13,17,20,25,29,34,40,45,52,58,65,73,80,89,97,106, %T A036404 116,125,136,146,157,169,180,193,205,218,232,245,260,274,289,305,320, %U A036404 337,353,370,388,405,424,442,461,481,500,521,541,562,584 %N A036404 a(n) = ceiling(n^2/5). %H A036404 <a href="/index/Rec#order_07">Index entries for linear recurrences with constant coefficients</a>, signature (2,-1,0,0,1,-2,1). %F A036404 G.f. -x*(1+x)*(x^2-x+1)^2 / ( (x^4+x^3+x^2+x+1)*(x-1)^3 ). - _R. J. Mathar_, Jan 22 2011 %K A036404 nonn,easy %O A036404 0,4 %A A036404 _N. J. A. Sloane_