| n | a(n) |
|---|---|
| 0 | 1 |
| 1 | 2 |
| 2 | 4 |
| 3 | 10 |
| 4 | 24 |
| 5 | 56 |
| 6 | 130 |
| 7 | 304 |
| 8 | 714 |
| 9 | 1678 |
| 10 | 3944 |
| 11 | 9276 |
| 12 | 21832 |
| 13 | 51408 |
| 14 | 121088 |
| 15 | 285288 |
| 16 | 672304 |
| 17 | 1584638 |
| 18 | 3735596 |
| 19 | 8807312 |
| 20 | 20766914 |
| 21 | 48970942 |
| 22 | 115487946 |
| 23 | 272371376 |
| 24 | 642404770 |
| 25 | 1515218012 |
| 26 | 3574025956 |
| 27 | 8430514614 |
| 28 | 19886678810 |
| 29 | 46911630678 |
| 30 | 110664280068 |
| 31 | 261060908326 |
[1,2,4,10,24,56,130,304,714,1678,3944,9276,21832, 51408,121088,285288,672304,1584638,3735596, 8807312,20766914,48970942,115487946,272371376, 642404770,1515218012,3574025956,8430514614, 19886678810,46911630678,110664280068,261060908326] |