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 | 2 |
| 3 | 6 |
| 4 | 23 |
| 5 | 104 |
| 6 | 537 |
| 7 | 3100 |
| 8 | 19693 |
| 9 | 136064 |
| 10 | 1013345 |
| 11 | 8076644 |
| 12 | 68486013 |
| 13 | 614797936 |
| 14 | 5818490641 |
| 15 | 57846681092 |
| 16 | 602259154853 |
| 17 | 6548439927680 |
| 18 | 74180742421185 |
| 19 | 873588590481988 |
| 20 | 10674437936521069 |
| 21 | 135097459659312176 |