The OEIS is supported by the many generous donors to the OEIS Foundation.
Reminder: The OEIS is hiring a new managing editor, and the application deadline is January 26.
Reminder: The OEIS is hiring a new managing editor, and the application deadline is January 26.
| n | a(n) |
|---|---|
| 0 | 1 |
| 1 | 3 |
| 2 | 20 |
| 3 | 126 |
| 4 | 924 |
| 5 | 6435 |
| 6 | 48620 |
| 7 | 352716 |
| 8 | 2704156 |
| 9 | 20058300 |
| 10 | 155117520 |
| 11 | 1166803110 |
| 12 | 9075135300 |
| 13 | 68923264410 |
| 14 | 538257874440 |
| 15 | 4116715363800 |
| 16 | 32247603683100 |
| 17 | 247959266474052 |
| 18 | 1946939425648112 |
| 19 | 15033633249770520 |
| 20 | 118264581564861424 |
[1,3,20,126,924,6435,48620,352716,2704156, 20058300,155117520,1166803110,9075135300, 68923264410,538257874440,4116715363800, 32247603683100,247959266474052,1946939425648112, 15033633249770520,118264581564861424] |