The OEIS is supported by the many generous donors to the OEIS Foundation.
| n | a(n) |
|---|---|
| 0 | 1 |
| 1 | 4 |
| 2 | 32 |
| 3 | 286 |
| 4 | 2688 |
| 5 | 26004 |
| 6 | 256334 |
| 7 | 2560352 |
| 8 | 25824768 |
| 9 | 262447684 |
| 10 | 2683152032 |
| 11 | 27565067600 |
| 12 | 284330359950 |
| 13 | 2942808943572 |
| 14 | 30546407611136 |
| 15 | 317867390671536 |
| 16 | 3314979452815360 |
| 17 | 34637849797078380 |
| 18 | 362544825234198020 |
| 19 | 3800439733237986800 |
| 20 | 39893311092729794688 |
[1,4,32,286,2688,26004,256334,2560352,25824768, 262447684,2683152032,27565067600,284330359950, 2942808943572,30546407611136,317867390671536, 3314979452815360,34637849797078380, 362544825234198020,3800439733237986800, 39893311092729794688] |