A131819 A131818 * A000012 as infinite lower triangular matrices. Triangle read by rows, partial sums starting from the right of A131818.

1, 4, 2, 8, 5, 3, 13, 9, 7, 4, 19, 14, 12, 9, 5, 26, 20, 18, 15, 11, 6, 34, 27, 25, 22, 18, 13, 7, 43, 35, 33, 30, 26, 21, 15, 8, 53, 44, 42, 39, 35, 30, 24, 17, 9, 64, 54, 52, 49, 45, 40, 34, 27, 19, 10, 76, 65, 63, 60, 56, 51, 45, 38, 30, 21, 11

Offset: 1

Author

Gary W. Adamson, Jul 18 2007

Keywords

• nonn
• tabl

Comments

Left column = A034856: (1, 4, 8, 13, 19, 26, 34, ...). Row sums = A131820: (1, 6, 16, 33, 59, 96, ...).

Examples

			First few rows of the triangle:
   1;
   4,  2;
   8,  5,  3;
  13,  9,  7,  4;
  19, 14, 12,  9,  5;
  26, 20, 18, 15, 11,  6;
  34, 27, 25, 22, 18, 13,  7;
  ...
		

Crossrefs

Cf. A131818, A000012, A131820, A034856.

Programs

PARI

tabl(nn) = {m131818 = matrix(nn, nn, n, k, if (k==1, n, if (k <= n, k, 0))); m000012 = matrix(nn, nn, n, k, (k<=n)); m131819 = m131818 * m000012; for (n = 1, nn, for (k = 1, n, print1(m131819[n, k], ", ");););} \\ Michel Marcus, Feb 12 2014

Extensions

More terms from Michel Marcus, Feb 12 2014