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 | 2 |
| 2 | 9 |
| 3 | 42 |
| 4 | 203 |
| 5 | 1085 |
| 6 | 6636 |
| 7 | 46662 |
| 8 | 373626 |
| 9 | 3363129 |
| 10 | 33632005 |
| 11 | 369953056 |
| 12 | 4439438037 |
| 13 | 57712696301 |
| 14 | 807977750594 |
| 15 | 12119666261970 |
| 16 | 193914660195396 |
| 17 | 3296549223326577 |
| 18 | 59337886019884371 |
| 19 | 1127419834377810364 |
| 20 | 22548396687556216135 |
| 21 | 473516330438680549461 |