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) |
|---|---|
| 1 | 1 |
| 2 | 1 |
| 3 | 2 |
| 4 | 8 |
| 5 | 38 |
| 6 | 234 |
| 7 | 1679 |
| 8 | 13802 |
| 9 | 127155 |
| 10 | 1297619 |
| 11 | 14516296 |
| 12 | 176640311 |
| 13 | 2322876382 |
| 14 | 32831464503 |
| 15 | 496399943530 |
| 16 | 7995690518504 |
| 17 | 136701790293581 |
| 18 | 2472679442088700 |
| 19 | 47180405307783443 |
| 20 | 947116124382018095 |
| 21 | 19954735355719570880 |
| 22 | 440286840550877179031 |