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 | 4 |
| 2 | 28 |
| 3 | 219 |
| 4 | 1804 |
| 5 | 15314 |
| 6 | 132572 |
| 7 | 1163565 |
| 8 | 10316924 |
| 9 | 92195488 |
| 10 | 829016968 |
| 11 | 7492106505 |
| 12 | 67991427828 |
| 13 | 619193535380 |
| 14 | 5655829748520 |
| 15 | 51794730347745 |
| 16 | 475390078267356 |
| 17 | 4371917301657488 |
| 18 | 40276635724273936 |