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 | 21 |
| 3 | 257 |
| 4 | 2989 |
| 5 | 34468 |
| 6 | 396500 |
| 7 | 4577274 |
| 8 | 52338705 |
| 9 | 600923375 |
| 10 | 6897569624 |
| 11 | 79170705722 |
| 12 | 908721438900 |
| 13 | 10430285080567 |
| 14 | 119719520002653 |
| 15 | 1374133015203548 |
| 16 | 15772280213569812 |
| 17 | 181033948036338279 |
| 18 | 2077904397828614231 |
| 19 | 23850149155575310594 |
| 20 | 273751580233289217307 |