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 | 1 |
| 3 | 2 |
| 4 | 5 |
| 5 | 16 |
| 6 | 63 |
| 7 | 293 |
| 8 | 1561 |
| 9 | 9321 |
| 10 | 61436 |
| 11 | 442134 |
| 12 | 3446077 |
| 13 | 28905485 |
| 14 | 259585900 |
| 15 | 2485120780 |
| 16 | 25267283367 |
| 17 | 271949606805 |
| 18 | 3089330120711 |
| 19 | 36943477086287 |
| 20 | 463943009361687 |
| 21 | 6105064699310785 |
| 22 | 84011389289865102 |