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) |
|---|---|
| 1 | 0 |
| 2 | 0 |
| 3 | 1 |
| 4 | 8 |
| 5 | 44 |
| 6 | 214 |
| 7 | 1000 |
| 8 | 4592 |
| 9 | 20888 |
| 10 | 94846 |
| 11 | 434973 |
| 12 | 2042836 |
| 13 | 9979086 |
| 14 | 51460622 |
| 15 | 283839957 |
| 16 | 1688139424 |
| 17 | 10859199656 |
| 18 | 75338888918 |
| 19 | 560740210491 |
| 20 | 4445766353604 |
| 21 | 37329808482989 |
| 22 | 330143634313064 |
| 23 | 3064464030121369 |