The OEIS is supported by the many generous donors to the OEIS Foundation.
| n | a(n) |
|---|---|
| 1 | 1 |
| 2 | 1 |
| 3 | 2 |
| 4 | 4 |
| 5 | 8 |
| 6 | 16 |
| 7 | 32 |
| 8 | 65 |
| 9 | 138 |
| 10 | 316 |
| 11 | 792 |
| 12 | 2142 |
| 13 | 6052 |
| 14 | 17316 |
| 15 | 49160 |
| 16 | 137109 |
| 17 | 374650 |
| 18 | 1004848 |
| 19 | 2658192 |
| 20 | 6982424 |
| 21 | 18351272 |
| 22 | 48607148 |
| 23 | 130447416 |
| 24 | 355542916 |
| 25 | 983250704 |
| 26 | 2749502132 |
| 27 | 7738681064 |
| 28 | 21826783844 |
| 29 | 61484999000 |
| 30 | 172649101544 |
[1,1,2,4,8,16,32,65,138,316,792,2142,6052,17316, 49160,137109,374650,1004848,2658192,6982424, 18351272,48607148,130447416,355542916,983250704, 2749502132,7738681064,21826783844,61484999000, 172649101544] |