The OEIS is supported by the many generous donors to the OEIS Foundation.
| n | a(n) |
|---|---|
| 0 | 0 |
| 1 | 0 |
| 2 | 1 |
| 3 | 3 |
| 4 | 7 |
| 5 | 15 |
| 6 | 32 |
| 7 | 70 |
| 8 | 157 |
| 9 | 357 |
| 10 | 815 |
| 11 | 1859 |
| 12 | 4232 |
| 13 | 9620 |
| 14 | 21853 |
| 15 | 49635 |
| 16 | 112747 |
| 17 | 256139 |
| 18 | 581944 |
| 19 | 1322210 |
| 20 | 3004145 |
| 21 | 6825557 |
| 22 | 15507867 |
| 23 | 35234183 |
| 24 | 80052656 |
| 25 | 181881000 |
| 26 | 413236953 |
| 27 | 938882307 |
| 28 | 2133159119 |
| 29 | 4846579847 |
| 30 | 11011525360 |
[0,0,1,3,7,15,32,70,157,357,815,1859,4232,9620, 21853,49635,112747,256139,581944,1322210,3004145, 6825557,15507867,35234183,80052656,181881000, 413236953,938882307,2133159119,4846579847, 11011525360] |