A134237 Triangle read by rows, a(1) = 1, n-th row n terms of: (2n-1, 2n, 2n+1, ..., followed by n).

1, 3, 2, 5, 6, 3, 7, 8, 9, 4, 9, 10, 11, 12, 5, 11, 12, 13, 14, 15, 6, 13, 14, 15, 16, 17, 18, 7, 15, 16, 17, 18, 19, 20, 21, 8, 17, 18, 19, 20, 21, 22, 23, 24, 9, 19, 20, 21, 22, 23, 24, 25, 26, 27, 10, 21, 22, 23, 24, 25, 26, 27, 28, 29, 30, 11, 23, 24, 25, 26, 27, 28, 29, 30, 31, 32, 33, 12

Offset: 1

Author

Gary W. Adamson, Oct 14 2007

Keywords

• nonn
• tabl

Comments

Row sums = A134238: (1, 5, 14, 28, 47, 71, 100, 134, ...).

Examples

			First few rows of the triangle:
   1;
   3,  2;
   5,  6,  3;
   7,  8,  9,  4;
   9, 10, 11, 12,  5;
  11, 12, 13, 14, 15,  6;
  13, 14, 15, 16, 17, 18,  7;
  ...
		

Crossrefs

Cf. A134238.

Programs

PARI

T(n, k) = if (k < n, (2*n-1) + (k-1), n);
tabl(nn) = for (n=1, nn, for (k=1, n, print1(T(n, k), ", ")); print); \\ Michel Marcus, Jul 13 2017

Extensions

Corrected and extended by Michel Marcus, Jul 13 2017