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 | 3 |
| 2 | 24 |
| 3 | 63 |
| 4 | 264 |
| 5 | 1374 |
| 6 | 3114 |
| 7 | 8937 |
| 8 | 60663 |
| 9 | 94863 |
| 10 | 545793 |
| 11 | 1989417 |
| 12 | 5477133 |
| 13 | 20736417 |
| 14 | 82395387 |
| 15 | 260191833 |
| 16 | 706399164 |
| 17 | 2428989417 |
| 18 | 9380293167 |
| 19 | 28105157886 |
| 20 | 99497231067 |
| 21 | 538479339417 |
| 22 | 1974763271886 |
| 23 | 4472135831667 |
| 24 | 14106593458167 |
| 25 | 62441868958167 |
| 26 | 244744764757083 |
| 27 | 836594274358167 |