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 | 19 |
| 3 | 51 |
| 4 | 201 |
| 5 | 723 |
| 6 | 2709 |
| 7 | 10161 |
| 8 | 38459 |
| 9 | 146297 |
| 10 | 559135 |
| 11 | 2145021 |
| 12 | 8255579 |
| 13 | 31861021 |
| 14 | 123256499 |
| 15 | 477823891 |
| 16 | 1855782329 |
| 17 | 7219352971 |
| 18 | 28125910829 |
| 19 | 109720617991 |
| 20 | 428537256449 |
| 21 | 1675561707271 |
| 22 | 6557869020329 |
| 23 | 25689734662771 |
| 24 | 100720871774981 |
| 25 | 395197661173123 |