The OEIS is supported by the many generous donors to the OEIS Foundation.
| n | a(n) |
|---|---|
| 2 | 1 |
| 3 | 123 |
| 4 | 4806 |
| 5 | 71410 |
| 6 | 583455 |
| 7 | 3232341 |
| 8 | 13675228 |
| 9 | 47502036 |
| 10 | 141991245 |
| 11 | 377162335 |
| 12 | 910842306 |
| 13 | 2033854758 |
| 14 | 4253012491 |
| 15 | 8411348505 |
| 16 | 15856955640 |
| 17 | 28673921896 |
| 18 | 49991146713 |
| 19 | 84387303171 |
| 20 | 138412872190 |
| 21 | 221253017370 |
| 22 | 345558093111 |
| 23 | 528471784093 |
| 24 | 792890261076 |
[1,123,4806,71410,583455,3232341,13675228, 47502036,141991245,377162335,910842306,2033854758, 4253012491,8411348505,15856955640,28673921896, 49991146713,84387303171,138412872190,221253017370, 345558093111,528471784093,792890261076] |