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 | 9 |
| 2 | 28 |
| 3 | 133 |
| 4 | 539 |
| 5 | 2322 |
| 6 | 9773 |
| 7 | 41501 |
| 8 | 175636 |
| 9 | 744273 |
| 10 | 3152359 |
| 11 | 13354306 |
| 12 | 56568617 |
| 13 | 239630337 |
| 14 | 1015087436 |
| 15 | 4299984173 |
| 16 | 18215017507 |
| 17 | 77160064914 |
| 18 | 326855259829 |
| 19 | 1384581132277 |
| 20 | 5865179743556 |
| 21 | 24845300179929 |
| 22 | 105246380344463 |
| 23 | 445830821750018 |
| 24 | 1888569667033489 |