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 | 7 |
| 3 | 52 |
| 4 | 385 |
| 5 | 2851 |
| 6 | 21112 |
| 7 | 156337 |
| 8 | 1157695 |
| 9 | 8572876 |
| 10 | 63483217 |
| 11 | 470101147 |
| 12 | 3481157680 |
| 13 | 25778407201 |
| 14 | 190892323447 |
| 15 | 1413581485732 |
| 16 | 10467747370465 |
| 17 | 77514976050451 |
| 18 | 574008074464552 |
| 19 | 4250601449403217 |
| 20 | 31476234369216175 |