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 A025573 #6 Sep 07 2019 22:04:00 %S A025573 1,4,19,98,526,2892,16159,91338,520794,2989688,17256275,100046894, %T A025573 582204290,3398722420,19894375665,116724946350,686260868346, %U A025573 4042058735880,23846068472626,140882925528892,833421929615236,4936088399361876,29266184138206509,173689743532678182 %N A025573 a(n) = T(2n,n-1), where T is the array defined in A025564. %K A025573 nonn %O A025573 1,2 %A A025573 _Clark Kimberling_ %E A025573 More terms from _Sean A. Irvine_, Sep 07 2019