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 | 1 |
| 1 | 1 |
| 2 | 2 |
| 3 | 6 |
| 4 | 24 |
| 5 | 118 |
| 6 | 672 |
| 7 | 4256 |
| 8 | 29176 |
| 9 | 212586 |
| 10 | 1625704 |
| 11 | 12930160 |
| 12 | 106242392 |
| 13 | 897210996 |
| 14 | 7756325952 |
| 15 | 68422701792 |
| 16 | 614341492144 |
| 17 | 5602330498170 |
| 18 | 51798365474872 |
| 19 | 484856381630288 |
| 20 | 4589003801130456 |
| 21 | 43870126242653020 |
| 22 | 423219224419273888 |
| 23 | 4116816114087389056 |
| 24 | 40351014094161799568 |
| 25 | 398270701521760650532 |