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 | 1 |
| 3 | 1 |
| 4 | 3 |
| 5 | 7 |
| 6 | 33 |
| 7 | 109 |
| 8 | 643 |
| 9 | 2623 |
| 10 | 17929 |
| 11 | 85349 |
| 12 | 652395 |
| 13 | 3517911 |
| 14 | 29484193 |
| 15 | 176844781 |
| 16 | 1605009651 |
| 17 | 10575269935 |
| 18 | 103033059513 |
| 19 | 738834271605 |
| 20 | 7676696689275 |
| 21 | 59466011617671 |
| 22 | 655467253898577 |
| 23 | 5451048833933693 |