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 | 0 |
| 1 | 1 |
| 2 | 13 |
| 3 | 148 |
| 4 | 1707 |
| 5 | 20686 |
| 6 | 266321 |
| 7 | 3652608 |
| 8 | 53339831 |
| 9 | 827870338 |
| 10 | 13624599309 |
| 11 | 237169578724 |
| 12 | 4356110013107 |
| 13 | 84220077081414 |
| 14 | 1710164008931657 |
| 15 | 36396070427846536 |
| 16 | 810244122520224111 |
| 17 | 18833465673721387018 |
| 18 | 456310533309915775301 |
| 19 | 11505888654389005045548 |