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 | 3 |
| 2 | 18 |
| 3 | 127 |
| 4 | 993 |
| 5 | 8268 |
| 6 | 71888 |
| 7 | 645087 |
| 8 | 5929527 |
| 9 | 55544315 |
| 10 | 528319662 |
| 11 | 5088941628 |
| 12 | 49539243900 |
| 13 | 486606281496 |
| 14 | 4816930145376 |
| 15 | 48005470976271 |
| 16 | 481262635723491 |
| 17 | 4850084768085465 |
| 18 | 49107197378659262 |
| 19 | 499298960719688343 |
| 20 | 5095861705240094097 |