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 A226234 #18 Sep 08 2013 17:33:36 %S A226234 1,1,1,1,4,1,1,9,126,1,1,16,1820,11440,1,1,25,12650,2042975,2042975,1, %T A226234 1,36,58905,94143280,7307872110,600805296,1,1,49,211876,2054455634, %U A226234 3348108992991,63205303218876,262596783764,1,1,64,635376,27540584512,488526937079580,401038568751465792,1118770292985239888,159518999862720,1 %N A226234 Triangle defined by T(n,k) = binomial(n^2, k^2), for n>=0, k=0..n, as read by rows. %C A226234 Row sums equal A206849. %C A226234 Antidiagonal sums equal A123165. %H A226234 Paul D. Hanna, <a href="/A226234/b226234.txt">Rows n = 0..30, as a flattened table of n, a(n) for n = 0..495</a> %e A226234 The triangle of coefficients C(n^2,k^2), n>=k, k=0..n, begins: %e A226234 1; %e A226234 1, 1; %e A226234 1, 4, 1; %e A226234 1, 9, 126, 1; %e A226234 1, 16, 1820, 11440, 1; %e A226234 1, 25, 12650, 2042975, 2042975, 1; %e A226234 1, 36, 58905, 94143280, 7307872110, 600805296, 1; %e A226234 1, 49, 211876, 2054455634, 3348108992991, 63205303218876, 262596783764, 1; %e A226234 1, 64, 635376, 27540584512, 488526937079580, 401038568751465792, 1118770292985239888, 159518999862720, 1; ... %o A226234 (PARI) {T(n,k)=binomial(n^2,k^2)} %o A226234 for(n=0,9,for(k=0,n,print1(T(n,k),", "));print("")) %Y A226234 Cf. A206849, A123165. %Y A226234 Cf. related triangles: A228902(exp), A209330, A228832, A228836. %K A226234 nonn,tabl %O A226234 0,5 %A A226234 _Paul D. Hanna_, Aug 24 2013