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 A108268 #7 Nov 23 2021 12:09:39 %S A108268 1,31,381,3431,26769,193705,1343521,9091270,60632419,401001030, %T A108268 2639871326,17339260251,113792427233,746807661549,4903854042841, %U A108268 32227106641988,211992209767971,1395903036647155,9200826759772935 %N A108268 Column 2 of triangle A108267. %o A108268 (PARI) %o A108268 a(n)=polcoeff((1-x)^(n+1)*sum(j=0,n,binomial(n+n*j+j,n*j+j)*x^j),2) %Y A108268 Cf. A108267. %K A108268 nonn %O A108268 2,2 %A A108268 _Paul D. Hanna_, May 29 2005 %E A108268 Offset corrected by _Andrey Zabolotskiy_, Nov 23 2021