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 A026067 #12 Mar 17 2021 08:54:24 %S A026067 52,84,123,170,225,290,364,448,542,648,765,894,1035,1190,1358,1540, %T A026067 1736,1948,2175,2418,2677,2954,3248,3560,3890,4240,4609,4998,5407, %U A026067 5838,6290,6764,7260,7780,8323,8890,9481,10098,10740,11408,12102,12824,13573,14350,15155,15990,16854 %N A026067 a(n) = (d(n)-r(n))/2, where d = A026066 and r is the periodic sequence with fundamental period (1,0,0,0). %H A026067 <a href="/index/Rec#order_07">Index entries for linear recurrences with constant coefficients</a>, signature (3,-3,1,1,-3,3,-1). %F A026067 G.f.: x^7*( 52-72*x+27*x^2+x^3+74*x^5-28*x^6-52*x^4 ) / ( (1+x)*(x^2+1)*(x-1)^4 ). - _R. J. Mathar_, Jun 23 2013 %Y A026067 Cf. A026066. %K A026067 nonn,easy %O A026067 7,1 %A A026067 _Clark Kimberling_