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 | 2 |
| 2 | 9 |
| 3 | 42 |
| 4 | 199 |
| 5 | 950 |
| 6 | 4554 |
| 7 | 21884 |
| 8 | 105323 |
| 9 | 507398 |
| 10 | 2446022 |
| 11 | 11796884 |
| 12 | 56912838 |
| 13 | 274630876 |
| 14 | 1325431956 |
| 15 | 6397576888 |
| 16 | 30882340531 |
| 17 | 149084312006 |
| 18 | 719736965358 |
| 19 | 3474807470756 |
| 20 | 16776410481266 |
| 21 | 80998307687668 |
| 22 | 391074406408716 |
| 23 | 1888199373821896 |
| 24 | 9116752061308798 |