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.

A143254 Triangle read by rows, T(n,k) = (4n-3)*(4k-3); 1<=k<=n.

Original entry on oeis.org

1, 5, 25, 9, 45, 81, 13, 65, 117, 169, 17, 85, 153, 221, 289, 21, 105, 189, 273, 357, 441, 25, 125, 225, 325, 425, 525, 625, 29, 145, 261, 377, 493, 609, 725, 841, 33, 165, 297, 429, 561, 693, 825, 957, 1089, 37, 185, 333, 481, 629, 777, 925, 1073, 1221, 1369
Offset: 1

Views

Author

Gary W. Adamson, Aug 02 2008

Keywords

Comments

Row sums = A100147: (1, 30, 135, 364, 765,...).

Examples

			First few rows of the triangle =
1;
5, 25;
9, 45, 81;
13, 65, 117, 169;
17, 85, 153, 221, 289;
21, 105, 189, 273, 357, 441;
...
T(5,3) = 153 = (4n-3)*(4k-3) = 17*9
		

Crossrefs

Programs

  • Mathematica
    Flatten[Table[(4 n - 3) (4 k - 3), {n, 10}, {k, n}]] (* Harvey P. Dale, Feb 28 2015 *)

Formula

Triangle read by rows, T(n,k) = (4n-3)*(4k-3); 1<=k<=n, where (4k-3) = A016813: (1, 5, 9, 13, 17,...). Let X = an infinite lower triangular matrix with (1, 5, 9, 13,...) in the main diagonal and the rest zeros. The triangle = X * A000012 * X, where A000012 = an infinite lower triangular matrix with all 1's: (1; 1,1; 1,1,1;...)