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 A184636 #15 Aug 28 2025 05:52:19 %S A184636 3,8,18,32,50,72,98,128,162,200,242,288,338,392,450,512,578,648,722, %T A184636 800,882,968,1058,1152,1250,1352,1458,1568,1682,1800,1922,2048,2178, %U A184636 2312,2450,2592,2738,2888,3042,3200,3362,3528,3698,3872,4050,4232,4418,4608,4802,5000,5202,5408,5618,5832,6050,6272,6498,6728,6962,7200,7442,7688,7938,8192,8450,8712,8978,9248,9522,9800 %N A184636 a(n) = floor(1/{(n^4+2*n)^(1/4)}), where {}=fractional part. %C A184636 Is a(n) = A001105(n) for n>=2 ? _R. J. Mathar_, Jan 28 2011 %H A184636 <a href="/index/Rec#order_03">Index entries for linear recurrences with constant coefficients</a>, signature (3, -3, 1). %F A184636 a(n)=floor(1/{(n^4+2*n)^(1/4)}), where {}=fractional part. %F A184636 It appears that a(n)=3a(n-1)-3a(n-2)+a(n-3) for n>=5, and that a(n)=2*n^2 for n>=2. %t A184636 p[n_]:=FractionalPart[(n^4+2*n)^(1/4)]; %t A184636 q[n_]:=Floor[1/p[n]]; %t A184636 Table[q[n], {n, 1, 80}] %t A184636 FindLinearRecurrence[Table[q[n], {n, 1, 1000}]] %t A184636 Join[{3},LinearRecurrence[{3,-3,1},{8,18,32},69]] (* _Ray Chandler_, Aug 02 2015 *) %Y A184636 Cf. A184536, A184635, A184637. %K A184636 nonn,changed %O A184636 1,1 %A A184636 _Clark Kimberling_, Jan 18 2011