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 | 4 |
| 3 | 13 |
| 4 | 46 |
| 5 | 199 |
| 6 | 1072 |
| 7 | 6985 |
| 8 | 53218 |
| 9 | 462331 |
| 10 | 4500244 |
| 11 | 48454957 |
| 12 | 571411270 |
| 13 | 7321388383 |
| 14 | 101249656696 |
| 15 | 1502852293009 |
| 16 | 23827244817322 |
| 17 | 401839065437635 |
| 18 | 7182224591785948 |
| 19 | 135607710526966261 |
| 20 | 2696935204638786574 |
| 21 | 56349204870460046887 |
| 22 | 1234002202313888987200 |