The OEIS is supported by the many generous donors to the OEIS Foundation.
| n | a(n) |
|---|---|
| 0 | 1 |
| 1 | 0 |
| 2 | 1 |
| 3 | 0 |
| 4 | 2 |
| 5 | 2 |
| 6 | 6 |
| 7 | 11 |
| 8 | 26 |
| 9 | 56 |
| 10 | 129 |
| 11 | 294 |
| 12 | 684 |
| 13 | 1599 |
| 14 | 3774 |
| 15 | 8961 |
| 16 | 21411 |
| 17 | 51421 |
| 18 | 124081 |
| 19 | 300667 |
| 20 | 731337 |
| 21 | 1785010 |
| 22 | 4370431 |
| 23 | 10731270 |
| 24 | 26419202 |
| 25 | 65198847 |
| 26 | 161262046 |
| 27 | 399692001 |
| 28 | 992559011 |
| 29 | 2469265633 |
| 30 | 6153306125 |
| 31 | 15357906136 |
| 32 | 38388056063 |
| 33 | 96086525311 |
| 34 | 240821963528 |
[1,0,1,0,2,2,6,11,26,56,129,294,684,1599,3774, 8961,21411,51421,124081,300667,731337,1785010, 4370431,10731270,26419202,65198847,161262046, 399692001,992559011,2469265633,6153306125, 15357906136,38388056063,96086525311,240821963528] |