The OEIS is supported by the many generous donors to the OEIS Foundation.
| n | a(n) |
|---|---|
| 0 | 1 |
| 1 | 1 |
| 2 | 2 |
| 3 | 5 |
| 4 | 14 |
| 5 | 36 |
| 6 | 90 |
| 7 | 216 |
| 8 | 507 |
| 9 | 1167 |
| 10 | 2640 |
| 11 | 5895 |
| 12 | 13020 |
| 13 | 28504 |
| 14 | 61937 |
| 15 | 133734 |
| 16 | 287194 |
| 17 | 613842 |
| 18 | 1306594 |
| 19 | 2771010 |
| 20 | 5857670 |
| 21 | 12346641 |
| 22 | 25955890 |
| 23 | 54436999 |
| 24 | 113924438 |
| 25 | 237949763 |
| 26 | 496101303 |
| 27 | 1032606162 |
| 28 | 2146019444 |
| 29 | 4453653132 |
| 30 | 9230534755 |
[1,1,2,5,14,36,90,216,507,1167,2640,5895,13020, 28504,61937,133734,287194,613842,1306594,2771010, 5857670,12346641,25955890,54436999,113924438, 237949763,496101303,1032606162,2146019444, 4453653132,9230534755] |