The OEIS is supported by the many generous donors to the OEIS Foundation.
| n | a(n) |
|---|---|
| 0 | 1 |
| 1 | 1 |
| 2 | 2 |
| 3 | 4 |
| 4 | 11 |
| 5 | 26 |
| 6 | 77 |
| 7 | 220 |
| 8 | 677 |
| 9 | 2098 |
| 10 | 6756 |
| 11 | 22101 |
| 12 | 74264 |
| 13 | 253684 |
| 14 | 883795 |
| 15 | 3130432 |
| 16 | 11275246 |
| 17 | 41240180 |
| 18 | 153117873 |
| 19 | 576634463 |
| 20 | 2201600769 |
| 21 | 8517634249 |
| 22 | 33378499157 |
| 23 | 132438117118 |
| 24 | 531873247805 |
| 25 | 2161293783123 |
| 26 | 8883906870289 |
| 27 | 36928576428885 |
| 28 | 155196725172548 |
| 29 | 659272353608609 |
| 30 | 2830200765183775 |
[1,1,2,4,11,26,77,220,677,2098,6756,22101,74264, 253684,883795,3130432,11275246,41240180,153117873, 576634463,2201600769,8517634249,33378499157, 132438117118,531873247805,2161293783123, 8883906870289,36928576428885,155196725172548, 659272353608609,2830200765183775] |