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 | 0 |
| 2 | 1 |
| 3 | 1 |
| 4 | 6 |
| 5 | 21 |
| 6 | 110 |
| 7 | 673 |
| 8 | 4312 |
| 9 | 34260 |
| 10 | 280212 |
| 11 | 2648581 |
| 12 | 26580840 |
| 13 | 292468333 |
| 14 | 3453838544 |
| 15 | 43672689816 |
| 16 | 590203920256 |
| 17 | 8458029201433 |
| 18 | 128528293405392 |
| 19 | 2059731511022935 |
| 20 | 34762308371221224 |
| 21 | 615898019175914166 |
| 22 | 11432263502365894916 |
| 23 | 221855824404176472115 |