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 A128563 #6 Jun 02 2020 01:20:34 %S A128563 1,4,12,29,61,120,222,392,669,1109,1792,2838,4413,6751,10184,15169, %T A128563 22332,32538,46955,67162,95288,134173,187593,260562,359682,493622, %U A128563 673736,914814,1236057,1662340,2225738,2967500,3940540,5212495,6869598 %N A128563 Column 2 of triangle A128562. %F A128563 a(n) is the coefficient of q^(2*n+6) in the q-binomial coefficient [2*n+5, n+2]. %o A128563 (PARI) a(n)=polcoeff(prod(j=n+3,2*n+5,1-q^j)/prod(j=1,n+3,1-q^j),2*n+6,q) %K A128563 nonn %O A128563 0,2 %A A128563 _Paul D. Hanna_, Mar 10 2007