The OEIS is supported by the many generous donors to the OEIS Foundation.
| n | a(n) |
|---|---|
| 1 | 1 |
| 2 | 20 |
| 3 | 77 |
| 4 | 117 |
| 5 | 278 |
| 6 | 1959 |
| 7 | 11044 |
| 8 | 36730 |
| 9 | 123887 |
| 10 | 598383 |
| 11 | 2919993 |
| 12 | 11429093 |
| 13 | 43919671 |
| 14 | 194434626 |
| 15 | 880889564 |
| 16 | 3627851352 |
| 17 | 14690154222 |
| 18 | 63196827262 |
| 19 | 276336307138 |
| 20 | 1159331148853 |
| 21 | 4807640087709 |
| 22 | 20468995961561 |
| 23 | 88006303609494 |
[1,20,77,117,278,1959,11044,36730,123887,598383, 2919993,11429093,43919671,194434626,880889564, 3627851352,14690154222,63196827262,276336307138, 1159331148853,4807640087709,20468995961561, 88006303609494] |