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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.

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.

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%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