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 A330798 #11 May 24 2023 03:57:01 %S A330798 1,2,2,6,15,9,20,84,112,48,70,420,900,825,275,252,1980,5940,8580,6006, %T A330798 1638,924,9009,35035,70070,76440,43316,9996,3432,40040,192192,495040, %U A330798 742560,651168,310080,62016,12870,175032,1002456,3174444,6104700,7325640,5372136,2206413,389367 %N A330798 Triangle read by rows, interpolating between the central binomial coefficients and the central coefficients of the Catalan triangle. T(n, k) for 0 <= k <= n. %H A330798 G. C. Greubel, <a href="/A330798/b330798.txt">Rows n = 0..50 of the triangle, flattened</a> %F A330798 T(n, k) := ((n+1)/(2*n+1))*binomial(2*n+1, n+k+1)*binomial(2*n+k, k). %F A330798 T(n, 0) = A000984(n). %F A330798 T(n, n) = A174687(n). %F A330798 Sum_{k=0..n} T(n, k) = A330801(n). %F A330798 Sum_{k=0..n} (-1)^k*T(n, k) = 0^n. - _G. C. Greubel_, May 23 2023 %e A330798 Triangle starts: %e A330798 n\k [0] [1] [2] [3] [4] [5] [6] [7] %e A330798 [0] 1 %e A330798 [1] 2, 2 %e A330798 [2] 6, 15, 9 %e A330798 [3] 20, 84, 112, 48 %e A330798 [4] 70, 420, 900, 825, 275 %e A330798 [5] 252, 1980, 5940, 8580, 6006, 1638 %e A330798 [6] 924, 9009, 35035, 70070, 76440, 43316, 9996 %e A330798 [7] 3432, 40040, 192192, 495040, 742560, 651168, 310080, 6201 %p A330798 alias(C=binomial): T := (n, k) -> ((n+1)/(2*n+1))*C(2*n+1, n+k+1)*C(2*n+k, k): %p A330798 seq(seq(T(n,k), k=0..n), n=0..8); %t A330798 T[n_, k_]:= ((n+1)/(n+k+1))*Binomial[n,k]*Binomial[2*n+k,n]; %t A330798 Table[T[n,k], {n,0,12}, {k,0,n}]//Flatten (* _G. C. Greubel_, May 23 2023 *) %o A330798 (Magma) %o A330798 A330798:= func< n,k | ((n+1)/(n+k+1))*Binomial(n,k)*Binomial(2*n+k,n) >; %o A330798 [A330798(n,k): k in [0..n], n in [0..12]]; // _G. C. Greubel_, May 23 2023 %o A330798 (SageMath) %o A330798 def A330798(n,k): return ((n+1)/(n+k+1))*binomial(n, k)*binomial(2*n+k, n) %o A330798 flatten([[A330798(n,k) for k in range(n+1)] for n in range(13)]) # _G. C. Greubel_, May 23 2023 %Y A330798 Cf. A000984, A033184, A174687, A330801. %K A330798 nonn,tabl %O A330798 0,2 %A A330798 _Peter Luschny_, Jan 02 2020