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 A027211 #12 Oct 25 2019 16:50:21
%S A027211 1,3,8,22,53,136,312,768,1712,4101,8971,21082,45507,105435,225347,
%T A027211 516424,1095353,2488480,5246176,11834584,24826412,55677436,116321132,
%U A027211 259585768,540454158,1201026646,2493149402,5520322840,11430160964
%N A027211 a(n) = Sum_{k=0..n} (k+1) * A026725(n, k).
%p A027211 A027211 := proc(n)
%p A027211 add( (k+1)*A026725(n,k),k=0..n) ;
%p A027211 end proc: # _R. J. Mathar_, Oct 21 2019
%K A027211 nonn
%O A027211 0,2
%A A027211 _Clark Kimberling_
%E A027211 Name corrected by _R. J. Mathar_, Oct 21 2019