The OEIS is supported by the many generous donors to the OEIS Foundation.
| n | a(n) |
|---|---|
| 1 | 21 |
| 2 | 397 |
| 3 | 4379 |
| 4 | 22972 |
| 5 | 91482 |
| 6 | 284360 |
| 7 | 764297 |
| 8 | 1797975 |
| 9 | 3883755 |
| 10 | 7729696 |
| 11 | 14517156 |
| 12 | 25811656 |
| 13 | 44024953 |
| 14 | 72163603 |
| 15 | 114677011 |
| 16 | 176842932 |
| 17 | 266174946 |
| 18 | 391374778 |
| 19 | 564396617 |
| 20 | 798717009 |
| 21 | 1112552471 |
| 22 | 1525915970 |
| 23 | 2065331568 |
| 24 | 2759616340 |
[21,397,4379,22972,91482,284360,764297,1797975, 3883755,7729696,14517156,25811656,44024953, 72163603,114677011,176842932,266174946,391374778, 564396617,798717009,1112552471,1525915970, 2065331568,2759616340] |