The OEIS is supported by the many generous donors to the OEIS Foundation.
| n | a(n) |
|---|---|
| 1 | 1 |
| 2 | 1 |
| 3 | 1 |
| 4 | 3 |
| 5 | 5 |
| 6 | 14 |
| 7 | 30 |
| 8 | 82 |
| 9 | 203 |
| 10 | 552 |
| 11 | 1458 |
| 12 | 4004 |
| 13 | 10956 |
| 14 | 30514 |
| 15 | 85259 |
| 16 | 240507 |
| 17 | 681571 |
| 18 | 1943472 |
| 19 | 5565744 |
| 20 | 16011492 |
| 21 | 46233297 |
| 22 | 133975566 |
| 23 | 389455910 |
| 24 | 1135431759 |
| 25 | 3319060758 |
| 26 | 9726061473 |
| 27 | 28565447104 |
| 28 | 84073146827 |
| 29 | 247924840773 |
| 30 | 732439856638 |
| 31 | 2167507140543 |
| 32 | 6424491527538 |
| 33 | 19070573498367 |
| 34 | 56688719414910 |
| 35 | 168733726744153 |
| 36 | 502859937709589 |
| 37 | 1500383417733522 |
| 38 | 4481672952197057 |
| 39 | 13400947416395067 |
| 40 | 40111136395590224 |
[1,1,1,3,5,14,30,82,203,552,1458,4004,10956,30514, 85259,240507,681571,1943472,5565744,16011492, 46233297,133975566,389455910,1135431759, 3319060758,9726061473,28565447104,84073146827, 247924840773,732439856638,2167507140543, 6424491527538,19070573498367,56688719414910, 168733726744153,502859937709589,1500383417733522, 4481672952197057,13400947416395067, 40111136395590224] |