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 A047880 #7 May 24 2021 00:34:17 %S A047880 0,5,5,9,12,19,25,35,41,54,63,78,88,106,118,139,152,175,191,217,233, %T A047880 262,281,312,332,366,388,425,448,487,513,555,581,626,655,702,732,782, %U A047880 814,867,900,955,991,1049,1085,1146,1185,1248,1288 %N A047880 a(n) = A047879(n) / 2. %K A047880 nonn %O A047880 0,2 %A A047880 _Clark Kimberling_ %E A047880 Name corrected by _Sean A. Irvine_, May 23 2021