A137633 Triangle read by rows, A000012 * A026794.

1, 2, 1, 4, 1, 1, 7, 2, 1, 1, 12, 3, 1, 1, 1, 19, 5, 2, 1, 1, 1, 30, 7, 3, 1, 1, 1, 1, 45, 11, 4, 2, 1, 1, 1, 1, 67, 15, 6, 3, 1, 1, 1, 1, 1, 97, 22, 8, 4, 2, 1, 1, 1, 1, 1, 139, 30, 11, 5, 3, 1, 1, 1, 1, 1, 1

Offset

1,2

Comments

Left border = A000070: (1, 2, 4, 7, 12, 19, 30, 45, ...).

Second column = A000041, the partition numbers: (1, 1, 2, 3, 5, 7, 11, ...).

Row sums = A016905: (1, 3, 6, 11, 18, 29, 44, ...).

Links

Table of n, a(n) for n=1..66.

Formula

A000012 * A026794 as infinite lower triangular matrices.

Example

First few rows of the triangle:
   1;
   2, 1;
   4, 1, 1;
   7, 2, 1, 1;
  12, 3, 1, 1, 1;
  19, 5, 2, 1, 1, 1;
  30, 7, 3, 1, 1, 1, 1;
  ...

Crossrefs

Cf. A000041, A000070, A016905, A026794.

Sequence in context: A099510 A348593 A211232 * A168533 A191314 A191306

Adjacent sequences: A137630 A137631 A137632 * A137634 A137635 A137636

Keyword

nonn,tabl

Author

Gary W. Adamson, Jan 31 2008

Status

approved