A135152 A004736 + A128174 - I, I = Identity matrix.

1, 2, 1, 4, 2, 1, 4, 4, 2, 1, 6, 4, 4, 2, 1, 6, 6, 4, 4, 2, 1, 8, 6, 6, 4, 4, 2, 1, 8, 8, 6, 6, 4, 4, 2, 1, 10, 8, 8, 6, 6, 4, 4, 2, 1, 10, 10, 8, 8, 6, 6, 4, 4, 2, 1

Offset

1,2

Comments

Row sums = A047838: (1, 3, 7, 11, 17, 23, 31, 39, ...). The triangle is a companion to A135151.

Links

Table of n, a(n) for n=1..55.

Formula

A004736 + A128174 - I, where I = Identity matrix, A004736 = (1; 2,1; 3,2,1; ...) and A128174 = (1; 0,1; 1,0,1; 0,1,0,1; ...).

Example

First few rows of the triangle:
  1;
  2, 1;
  4, 2, 1;
  4, 4, 2, 1;
  6, 4, 4, 2, 1;
  6, 6, 4, 4, 2, 1;
  8, 6, 6, 4, 4, 2, 1;
  ...

Crossrefs

Cf. A135151, A047838, A004736, A128174.

Sequence in context: A304624 A083653 A278290 * A329504 A147542 A347069

Adjacent sequences: A135149 A135150 A135151 * A135153 A135154 A135155

Keyword

nonn,tabl

Author

Gary W. Adamson, Nov 21 2007

Status

approved