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) |
|---|---|
| 1 | 1 |
| 2 | 3 |
| 3 | 15 |
| 4 | 130 |
| 5 | 1565 |
| 6 | 23331 |
| 7 | 411775 |
| 8 | 8388612 |
| 9 | 193710249 |
| 10 | 5000000005 |
| 11 | 142655835311 |
| 12 | 4458050224134 |
| 13 | 151437553296133 |
| 14 | 5556003412779015 |
| 15 | 218946945190429695 |
| 16 | 9223372036854775816 |
| 17 | 413620130943168382097 |
| 18 | 19673204037648268787721 |