The OEIS is supported by the many generous donors to the OEIS Foundation.
| n | a(n) |
|---|---|
| 1 | 21 |
| 2 | 46 |
| 3 | 96 |
| 4 | 196 |
| 5 | 396 |
| 6 | 796 |
| 7 | 1596 |
| 8 | 3196 |
| 9 | 6396 |
| 10 | 12796 |
| 11 | 25596 |
| 12 | 51196 |
| 13 | 102396 |
| 14 | 204796 |
| 15 | 409596 |
| 16 | 819196 |
| 17 | 1638396 |
| 18 | 3276796 |
| 19 | 6553596 |
| 20 | 13107196 |
| 21 | 26214396 |
| 22 | 52428796 |
| 23 | 104857596 |
| 24 | 209715196 |
| 25 | 419430396 |
| 26 | 838860796 |
| 27 | 1677721596 |
| 28 | 3355443196 |
[21,46,96,196,396,796,1596,3196,6396,12796,25596, 51196,102396,204796,409596,819196,1638396,3276796, 6553596,13107196,26214396,52428796,104857596, 209715196,419430396,838860796,1677721596, 3355443196] |