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 | 7 |
| 3 | 42 |
| 4 | 245 |
| 5 | 1428 |
| 6 | 8323 |
| 7 | 48510 |
| 8 | 282737 |
| 9 | 1647912 |
| 10 | 9604735 |
| 11 | 55980498 |
| 12 | 326278253 |
| 13 | 1901689020 |
| 14 | 11083855867 |
| 15 | 64601446182 |
| 16 | 376524821225 |
| 17 | 2194547481168 |
| 18 | 12790760065783 |
| 19 | 74550012913530 |
| 20 | 434509317415397 |