cp's OEIS Frontend

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.

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A381883 Triangle read by rows: T(n, k) = binomial(2*n - 1, k).

Original entry on oeis.org

1, 1, 1, 1, 3, 3, 1, 5, 10, 10, 1, 7, 21, 35, 35, 1, 9, 36, 84, 126, 126, 1, 11, 55, 165, 330, 462, 462, 1, 13, 78, 286, 715, 1287, 1716, 1716, 1, 15, 105, 455, 1365, 3003, 5005, 6435, 6435, 1, 17, 136, 680, 2380, 6188, 12376, 19448, 24310, 24310
Offset: 0

Views

Author

Peter Luschny, Mar 15 2025

Keywords

Examples

			Triangle starts:
  [0] 1;
  [1] 1,  1;
  [2] 1,  3,   3;
  [3] 1,  5,  10,  10;
  [4] 1,  7,  21,  35,   35;
  [5] 1,  9,  36,  84,  126,  126;
  [6] 1, 11,  55, 165,  330,  462,  462;
  [7] 1, 13,  78, 286,  715, 1287, 1716, 1716;
  [8] 1, 15, 105, 455, 1365, 3003, 5005, 6435, 6435;
		

Crossrefs

Cf. A007318 (Pascal), A088218 (main diagonal), A114121 (row sums), A262977 (central terms).

Programs

  • Maple
    T := (n, k) -> binomial(2*n - 1, k):
    seq(seq(T(n, k), k = 0..n), n = 0..9);
  • Mathematica
    T[n_,k_]:=Binomial[2n-1,k];Table[T[n,k],{n,0,9},{k,0,n}]//Flatten (* James C. McMahon, Apr 02 2025 *)
Previous Showing 31-31 of 31 results.