A131248 2*A004070 - A000012.

1, 1, 1, 1, 3, 1, 1, 3, 5, 1, 1, 3, 7, 7, 1, 1, 3, 7, 13, 9, 1, 1, 3, 7, 15, 21, 11, 1, 1, 3, 7, 15, 29, 31, 13, 1, 1, 3, 7, 15, 31, 51, 43, 15, 1, 1, 3, 7, 15, 31, 61, 83, 57, 17, 1

Offset

0,5

Comments

Row sums = A104161: (1, 2, 5, 10, 19, 34, 59, ...).

Links

Table of n, a(n) for n=0..54.

Formula

2*A004070 - A000012 as infinite lower triangular matrices. Reversal triangle of A131247, read by rows.

Example

First few rows of the triangle:
  1;
  1,  1;
  1,  3,  1;
  1,  3,  5,  1;
  1,  3,  7,  7,  1;
  1,  3,  7, 13,  9,  1;
  1,  3,  7, 15, 21, 11,  1;
  1,  3,  7, 15, 29, 31, 13,  1;
  ...

Crossrefs

Cf. A004070, A000012, A104161, A131247.

Sequence in context: A246685 A218618 A271451 * A116445 A110291 A152027

Adjacent sequences: A131245 A131246 A131247 * A131249 A131250 A131251

Keyword

nonn,tabl

Author

Gary W. Adamson, Jun 23 2007

Status

approved