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) |
|---|---|
| 3 | 15 |
| 4 | 198 |
| 5 | 1610 |
| 6 | 10575 |
| 7 | 61845 |
| 8 | 336924 |
| 9 | 1751076 |
| 10 | 8801325 |
| 11 | 43141175 |
| 12 | 207347778 |
| 13 | 980828238 |
| 14 | 4578689115 |
| 15 | 21135851625 |
| 16 | 96628899960 |
| 17 | 438068838536 |
| 18 | 1971349880985 |
| 19 | 8813183238315 |
| 20 | 39169902510270 |
| 21 | 173172640973010 |