A138057 Triangle read by rows: row n consists of 0 followed by n (n+1)'s with alternating signs.

0, 0, -2, 0, -3, 3, 0, -4, 4, -4, 0, -5, 5, -5, 5, 0, -6, 6, -6, 6, -6, 0, -7, 7, -7, 7, -7, 7, 0, -8, 8, -8, 8, -8, 8, -8, 0, -9, 9, -9, 9, -9, 9, -9, 9, 0, -10, 10, -10, 10, -10, 10, -10, 10, -10

Offset

0,3

Links

Paolo Xausa, Table of n, a(n) for n = 0..1325 (rows 0..50 of the triangle, flattened).

Formula

T(n,k) = [k>0]*(n+1)*(-1)^k, with n >= 0 and 0 <= k <= n, where [] is the Iverson bracket. - Paolo Xausa, Nov 10 2023

Example

From Paolo Xausa, Nov 10 2023: (Start)
Triangle begins:
  n\k|  0   1   2   3   4  ...
  ---+---------------------
   0 |  0;
   1 |  0, -2;
   2 |  0, -3,  3;
   3 |  0, -4,  4, -4;
   4 |  0, -5,  5, -5,  5;
  ... (End)

Mathematica

Array[Join[{0}, (-1)^Range[#](#+1)]&, 15, 0] (* Paolo Xausa, Nov 10 2023 *)

Crossrefs

Cf. A131738.

Sequence in context: A369280 A127449 A328911 * A053727 A265208 A265020

Adjacent sequences: A138054 A138055 A138056 * A138058 A138059 A138060

Keyword

tabl,sign

Author

Paul Curtz, May 02 2008

Status

approved