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 | 0 |
| 2 | 1 |
| 3 | 12 |
| 4 | 102 |
| 5 | 760 |
| 6 | 5295 |
| 7 | 35364 |
| 8 | 228956 |
| 9 | 1445616 |
| 10 | 8936685 |
| 11 | 54252220 |
| 12 | 324214242 |
| 13 | 1911205608 |
| 14 | 11132579003 |
| 15 | 64170616020 |
| 16 | 366497915640 |
| 17 | 2076171038176 |
| 18 | 11676266706969 |
| 19 | 65242364726124 |
| 20 | 362433045180830 |
| 21 | 2002838101907160 |
| 22 | 11015341078090503 |
| 23 | 60321223747375492 |