A081580 as a triangular array
| | | | | | | | | | | 1 |
| | | | | | | | | | | 1 | | 1 |
| | | | | | | | | | 1 | | 7 | | 1 |
| | | | | | | | | 1 | | 13 | | 13 | | 1 |
| | | | | | | | 1 | | 19 | | 61 | | 19 | | 1 |
| | | | | | | 1 | | 25 | | 145 | | 145 | | 25 | | 1 |
| | | | | | 1 | | 31 | | 265 | | 595 | | 265 | | 31 | | 1 |
| | | | | 1 | | 37 | | 421 | | 1585 | | 1585 | | 421 | | 37 | | 1 |
| | | | 1 | | 43 | | 613 | | 3331 | | 6145 | | 3331 | | 613 | | 43 | | 1 |
| | | 1 | | 49 | | 841 | | 6049 | | 17401 | | 17401 | | 6049 | | 841 | | 49 | | 1 |
| | 1 | | 55 | | 1105 | | 9955 | | 40105 | | 65527 | | 40105 | | 9955 | | 1105 | | 55 | | 1 |
|
A081580 as a square array
1 | 1 | 1 | 1 | 1 | 1 | 1 | 1 | 1 | 1 | 1
| 1 | 7 | 13 | 19 | 25 | 31 | 37 | 43 | 49 | 55
| 1 | 13 | 61 | 145 | 265 | 421 | 613 | 841 | 1105
| 1 | 19 | 145 | 595 | 1585 | 3331 | 6049 | 9955
| 1 | 25 | 265 | 1585 | 6145 | 17401 | 40105
| 1 | 31 | 421 | 3331 | 17401 | 65527
| 1 | 37 | 613 | 6049 | 40105
| 1 | 43 | 841 | 9955
| 1 | 49 | 1105
| 1 | 55
| 1
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A081580 as an upper right triangle
1 | 1 | 1 | 1 | 1 | 1 | 1 | 1 | 1 | 1 | 1
| | 1 | 7 | 13 | 19 | 25 | 31 | 37 | 43 | 49 | 55
| | | 1 | 13 | 61 | 145 | 265 | 421 | 613 | 841 | 1105
| | | | 1 | 19 | 145 | 595 | 1585 | 3331 | 6049 | 9955
| | | | | 1 | 25 | 265 | 1585 | 6145 | 17401 | 40105
| | | | | | 1 | 31 | 421 | 3331 | 17401 | 65527
| | | | | | | 1 | 37 | 613 | 6049 | 40105
| | | | | | | | 1 | 43 | 841 | 9955
| | | | | | | | | 1 | 49 | 1105
| | | | | | | | | | 1 | 55
| | | | | | | | | | | 1
|
|