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 A190088 #16 Sep 08 2022 08:45:56 %S A190088 1,1,3,1,15,5,1,36,70,7,1,66,330,210,9,1,105,1001,1716,495,11,1,153, %T A190088 2380,8008,6435,1001,13,1,210,4845,27132,43758,19448,1820,15,1,276, %U A190088 8855,74613,203490,184756,50388,3060,17,1,351,14950,177100,735471,1144066,646646,116280,4845,19 %N A190088 Triangle of binomial coefficients binomial(3*n-k+1,3*n-3*k+1). %C A190088 Row sums = A190089. %C A190088 Diagonal sums = A190090. %H A190088 G. C. Greubel, <a href="/A190088/b190088.txt">Table of n, a(n) for the first 100 rows, flattened</a> %e A190088 Triangle begins: %e A190088 1 %e A190088 1, 3 %e A190088 1, 15, 5 %e A190088 1, 36, 70, 7 %e A190088 1, 66, 330, 210, 9 %e A190088 1, 105, 1001, 1716, 495, 11 %e A190088 1, 153, 2380, 8008, 6435, 1001, 13 %e A190088 1, 210, 4845, 27132, 43758, 19448, 1820, 15 %e A190088 1, 276, 8855, 74613, 203490, 184756, 50388, 3060, 17 %t A190088 Flatten[Table[Binomial[3n - k + 1, 3n - 3k + 1], {n, 0, 8}, {k, 0, n}]] %o A190088 (Maxima) create_list(binomial(3*n-k+1,3*n-3*k+1),n,0,12,k,0,n); %o A190088 (PARI) for(n=0,10, for(k=0,n, print1(binomial(3*n-k+1, 3*n-3*k+1), ", "))) \\ _G. C. Greubel_, Mar 04 2018 %o A190088 (Magma) /* As triangle */ [[Binomial(3*n-k+1, 3*n-3*k+1): k in [0..n]]: n in [0..10]]; // _G. C. Greubel_, Mar 04 2018 %Y A190088 Cf. A190089, A190090. %K A190088 nonn,easy,tabl %O A190088 0,3 %A A190088 _Emanuele Munarini_, May 04 2011