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 | 27 |
| 2 | 129 |
| 3 | 483 |
| 4 | 2117 |
| 5 | 9337 |
| 6 | 42249 |
| 7 | 193493 |
| 8 | 895517 |
| 9 | 4176897 |
| 10 | 19605239 |
| 11 | 92495573 |
| 12 | 438260309 |
| 13 | 2084105193 |
| 14 | 9941672807 |
| 15 | 47552376493 |
| 16 | 227988078573 |
| 17 | 1095365516417 |
| 18 | 5272454219583 |
| 19 | 25420784798597 |
| 20 | 122748340134507 |