| n | a(n) |
|---|---|
| 1 | 1 |
| 2 | 0 |
| 3 | 2 |
| 4 | 2 |
| 5 | 6 |
| 6 | 14 |
| 7 | 34 |
| 8 | 82 |
| 9 | 214 |
| 10 | 566 |
| 11 | 1482 |
| 12 | 4058 |
| 13 | 10950 |
| 14 | 30406 |
| 15 | 83786 |
| 16 | 235714 |
| 17 | 658286 |
| 18 | 1874254 |
| 19 | 5293674 |
| 20 | 15189810 |
| 21 | 43312542 |
| 22 | 125075238 |
| 23 | 359185586 |
| 24 | 1043712922 |
| 25 | 3015569582 |
| 26 | 8800146182 |
| 27 | 25565402802 |
| 28 | 74918274562 |
| 29 | 218572345718 |
| 30 | 642783954238 |
| 31 | 1882606578002 |
[1,0,2,2,6,14,34,82,214,566,1482,4058,10950,30406, 83786,235714,658286,1874254,5293674,15189810, 43312542,125075238,359185586,1043712922, 3015569582,8800146182,25565402802,74918274562, 218572345718,642783954238,1882606578002] |