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 | 11 |
| 4 | 61 |
| 5 | 407 |
| 6 | 3232 |
| 7 | 25093 |
| 8 | 211519 |
| 9 | 1745873 |
| 10 | 15637681 |
| 11 | 135802469 |
| 12 | 1224719101 |
| 13 | 11101010101 |
| 14 | 102829245283 |
| 15 | 929203539823 |
| 16 | 8708547008547 |
| 17 | 80952373015873 |
| 18 | 753731343283582 |
| 19 | 7074829931292517 |