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 | 1 |
| 2 | 3 |
| 3 | 13 |
| 4 | 97 |
| 5 | 621 |
| 6 | 6571 |
| 7 | 58633 |
| 8 | 779073 |
| 9 | 9317017 |
| 10 | 138628531 |
| 11 | 1977676581 |
| 12 | 37384244833 |
| 13 | 620735382853 |
| 14 | 12434855135067 |
| 15 | 245117537189281 |
| 16 | 5651550278494081 |
| 17 | 123266430844431153 |
| 18 | 3128700944169196003 |