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 A024221 #8 Jun 25 2019 22:21:54
%S A024221 12,163,891,3256,9340,22757,49254,97430,179537,312394,518402,826655,
%T A024221 1274155,1907129,2782449,3969144,5550027,7623415,10304946,13729509,
%U A024221 18053268,23455784,30142248,38345805,48329989,60391250,74861587,92111285,112551745
%N A024221 [ (4th elementary symmetric function of S(n))/(first elementary symmetric function of S(n)) ], where S(n) = {first n+3 positive integers congruent to 1 mod 3}.
%F A024221 a(n) = floor(A024214(n) / A000326(n+3)). - _Sean A. Irvine_, Jun 25 2019
%K A024221 nonn
%O A024221 1,1
%A A024221 _Clark Kimberling_