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 | 12 |
| 3 | 87 |
| 4 | 504 |
| 5 | 2565 |
| 6 | 11988 |
| 7 | 52731 |
| 8 | 221616 |
| 9 | 898857 |
| 10 | 3542940 |
| 11 | 13640319 |
| 12 | 51490728 |
| 13 | 191141613 |
| 14 | 699376356 |
| 15 | 2527001955 |
| 16 | 9030245472 |
| 17 | 31955015889 |
| 18 | 112093661484 |
| 19 | 390132432423 |
| 20 | 1348223301720 |
| 21 | 4629287423061 |
| 22 | 15802106905332 |
| 23 | 53651151578187 |
| 24 | 181257000301584 |