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 | 5 |
| 3 | 26 |
| 4 | 123 |
| 5 | 555 |
| 6 | 2440 |
| 7 | 10569 |
| 8 | 45381 |
| 9 | 193834 |
| 10 | 825275 |
| 11 | 3506867 |
| 12 | 14883984 |
| 13 | 63124593 |
| 14 | 267596485 |
| 15 | 1134071130 |
| 16 | 4805348667 |
| 17 | 20359308187 |
| 18 | 86252640920 |
| 19 | 365396207993 |
| 20 | 1547906421765 |
| 21 | 6557202405546 |
| 22 | 27777188626555 |
| 23 | 117667194149091 |
| 24 | 498449204352288 |