The OEIS is supported by the many generous donors to the OEIS Foundation.
| n | a(n) |
|---|---|
| 1 | 1 |
| 2 | 9 |
| 3 | 45 |
| 4 | 155 |
| 5 | 420 |
| 6 | 966 |
| 7 | 1974 |
| 8 | 3690 |
| 9 | 6435 |
| 10 | 10615 |
| 11 | 16731 |
| 12 | 25389 |
| 13 | 37310 |
| 14 | 53340 |
| 15 | 74460 |
| 16 | 101796 |
| 17 | 136629 |
| 18 | 180405 |
| 19 | 234745 |
| 20 | 301455 |
| 21 | 382536 |
| 22 | 480194 |
| 23 | 596850 |
| 24 | 735150 |
| 25 | 897975 |
| 26 | 1088451 |
| 27 | 1309959 |
| 28 | 1566145 |
| 29 | 1860930 |
| 30 | 2198520 |
| 31 | 2583416 |
| 32 | 3020424 |
| 33 | 3514665 |
[1,9,45,155,420,966,1974,3690,6435,10615,16731, 25389,37310,53340,74460,101796,136629,180405, 234745,301455,382536,480194,596850,735150,897975, 1088451,1309959,1566145,1860930,2198520,2583416, 3020424,3514665] |