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 A280089 #9 Dec 25 2016 15:43:40
%S A280089 1,2,27,100,245,486,847,1352,2025,2890,3971,5292,6877,8750,10935,
%T A280089 13456,16337,19602,23275,27380,31941,36982,42527,48600,55225,62426,
%U A280089 70227,78652,87725,97470,107911,119072,130977,143650,157115,171396,186517,202502,219375
%N A280089 a(n) = 4 * n^3 - 3 * n + 1.
%H A280089 Daniel Suteu, <a href="/A280089/b280089.txt">Table of n, a(n) for n = 0..750</a>
%F A280089 a(n) = (2n - 1)^2 * (n + 1).
%F A280089 Prod_{k >= 1}(A033430(k) / a(k)) = Pi.
%t A280089 Table[4n^3 - 3n + 1, {n, 0, 39}] (* _Alonso del Arte_, Dec 25 2016 *)
%o A280089 (PARI) a(n) = (2*n-1)^2 * (n+1).
%Y A280089 Cf. A033430.
%K A280089 nonn,easy
%O A280089 0,2
%A A280089 _Daniel Suteu_, Dec 25 2016