A131844 3*A131821 - 2.

1, 4, 4, 7, 1, 7, 10, 1, 1, 10, 13, 1, 1, 1, 13, 16, 1, 1, 1, 1, 16, 19, 1, 1, 1, 1, 1, 19, 22, 1, 1, 1, 1, 1, 1, 22, 25, 1, 1, 1, 1, 1, 1, 1, 25, 28, 1, 1, 1, 1, 1, 1, 1, 1, 28, 31, 1, 1, 1, 1, 1, 1, 1, 1, 1, 31, 34, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 34, 37, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 37, 40, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 40

Offset

0,2

Comments

Row sums = A016993, (7n + 1): (1, 8, 15, 22, 29, ...).

Links

Table of n, a(n) for n=0..104.

Formula

3*A131821 - 2 as infinite lower triangular matrices.

Infinite lower triangular matrix, (3n + 1): (1, 4, 7, 10, ...) as right and left borders and the rest 1's.

Example

First few rows of the triangle:
   1;
   4,  4;
   7,  1,  7;
  10,  1,  1, 10;
  13,  1,  1,  1, 13;
  16,  1,  1,  1,  1, 16;
  ...

Crossrefs

Cf. A131821, A016993.

Sequence in context: A282468 A196463 A021695 * A344212 A010476 A020762

Adjacent sequences: A131841 A131842 A131843 * A131845 A131846 A131847

Keyword

nonn,tabl,changed

Author

Gary W. Adamson, Jul 22 2007

Extensions

More terms from Russ Cox, Apr 18 2024

Status

approved