A131053 A000012 * A131047.

1, 1, 2, 2, 2, 3, 2, 6, 3, 4, 3, 6, 13, 4, 5, 3, 12, 13, 24, 5, 6, 4, 12, 34, 24, 40, 6, 7, 4, 20, 34, 80, 40, 62, 7, 8, 5, 20, 70, 80, 166, 62, 91, 8, 9

Offset

1,3

Comments

Row sums = (2^n - 1): (1, 3, 7, 15, ...).

Left border = A004526: (1, 1, 2, 2, 3, 3, ...).

A131052 = A131047 * A000012.

Links

Table of n, a(n) for n=1..45.

Formula

A000012 * A131047 as infinite lower triangular matrices.

Example

First few rows of the triangle:
  1;
  1,  2;
  2,  2,  3;
  2,  6,  3,  4;
  3,  6, 13,  4,  5;
  3, 12, 13, 24,  5,  6;
  4, 12, 34, 24, 40,  6,  7;
  ...

Crossrefs

Cf. A131047, A000012, A131052, A004526.

Sequence in context: A058726 A058614 A122765 * A219281 A125600 A084053

Adjacent sequences: A131050 A131051 A131052 * A131054 A131055 A131056

Keyword

nonn,tabl

Author

Gary W. Adamson, Jun 12 2007

Status

approved