This is a front-end for the Online Encyclopedia of Integer Sequences, made by Christian Perfect. The idea is to provide OEIS entries in non-ancient HTML, and then to think about how they're presented visually. The source code is on GitHub.
| n | a(n) |
|---|---|
| 0 | 0 |
| 1 | 0 |
| 2 | 1 |
| 3 | 7 |
| 4 | 35 |
| 5 | 155 |
| 6 | 651 |
| 7 | 2667 |
| 8 | 10795 |
| 9 | 43435 |
| 10 | 174251 |
| 11 | 698027 |
| 12 | 2794155 |
| 13 | 11180715 |
| 14 | 44731051 |
| 15 | 178940587 |
| 16 | 715795115 |
| 17 | 2863245995 |
| 18 | 11453115051 |
| 19 | 45812722347 |
| 20 | 183251413675 |
| 21 | 733006703275 |
| 22 | 2932028910251 |
| 23 | 11728119835307 |
| 24 | 46912487729835 |