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 | 1 |
| 2 | 2 |
| 3 | 12 |
| 4 | 45 |
| 5 | 200 |
| 6 | 832 |
| 7 | 3549 |
| 8 | 14994 |
| 9 | 63580 |
| 10 | 269225 |
| 11 | 1140624 |
| 12 | 4831488 |
| 13 | 20466953 |
| 14 | 86698690 |
| 15 | 367262700 |
| 16 | 1555747893 |
| 17 | 6590256856 |
| 18 | 27916771136 |
| 19 | 118257348165 |
| 20 | 500946152850 |
| 21 | 2122041977276 |
| 22 | 8989114033297 |
| 23 | 38078498156832 |
| 24 | 161303106585600 |
| 25 | 683290924620625 |
| 26 | 2894466804871682 |