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 | 3 |
| 2 | 15 |
| 3 | 99 |
| 4 | 783 |
| 5 | 6987 |
| 6 | 67671 |
| 7 | 694035 |
| 8 | 7418943 |
| 9 | 81800091 |
| 10 | 923720679 |
| 11 | 10630297827 |
| 12 | 124224709455 |
| 13 | 1470172954347 |
| 14 | 17585028636279 |
| 15 | 212248303720371 |
| 16 | 2581823992868703 |