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 A032526 #24 Aug 15 2025 10:38:21
%S A032526 0,2,10,22,40,62,90,122,160,202,250,302,360,422,490,562,640,722,810,
%T A032526 902,1000,1102,1210,1322,1440,1562,1690,1822,1960,2102,2250,2402,2560,
%U A032526 2722,2890,3062,3240,3422,3610,3802,4000,4202,4410,4622,4840,5062
%N A032526 a(n) = floor(5*n^2/2).
%H A032526 <a href="/index/Rec#order_04">Index entries for linear recurrences with constant coefficients</a>, signature (2,0,-2,1).
%F A032526 a(n) = 2n^2 + floor(n^2/2). - _Wesley Ivan Hurt_, Jun 14 2013
%F A032526 From _Bruno Berselli_, Jun 14 2013: (Start)
%F A032526 G.f.: 2*x*(1+3*x+x^2)/((1+x)*(1-x)^3).
%F A032526 a(n) = 2*A032527(n). (End)
%F A032526 Sum_{n>=1} 1/a(n) = Pi^2/60 + tan(Pi/(2*sqrt(5)))*Pi/(2*sqrt(5)). - _Amiram Eldar_, Aug 15 2025
%p A032526 A032526:=n->floor(5*n^2/2): seq(A032526(n), n=0..100); # _Wesley Ivan Hurt_, Feb 03 2017
%t A032526 Table[Floor[5 n^2/2], {n, 0, 50}] (* _Bruno Berselli_, Jun 14 2013 *)
%t A032526 LinearRecurrence[{2,0,-2,1},{0,2,10,22},50] (* _Harvey P. Dale_, Dec 14 2016 *)
%o A032526 (Magma) [Floor(5*n^2/2): n in [0..50]]; // _Bruno Berselli_, Jun 14 2013
%Y A032526 Cf. A032527.
%K A032526 nonn,easy
%O A032526 0,2
%A A032526 _N. J. A. Sloane_