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 | 4 |
| 2 | 20 |
| 3 | 126 |
| 4 | 980 |
| 5 | 9186 |
| 6 | 101492 |
| 7 | 1296934 |
| 8 | 18868652 |
| 9 | 308478492 |
| 10 | 5605768476 |
| 11 | 112198139500 |
| 12 | 2454071216496 |
| 13 | 58267971181456 |
| 14 | 1493114371576942 |
| 15 | 41084194594171729 |
| 16 | 1208473333806735096 |
| 17 | 37849717704435895370 |