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 | 4 |
| 2 | 17 |
| 3 | 71 |
| 4 | 295 |
| 5 | 1221 |
| 6 | 5040 |
| 7 | 20761 |
| 8 | 85380 |
| 9 | 350659 |
| 10 | 1438568 |
| 11 | 5896098 |
| 12 | 24145941 |
| 13 | 98812861 |
| 14 | 404118745 |
| 15 | 1651811920 |
| 16 | 6748282361 |
| 17 | 27556753703 |
| 18 | 112482005583 |
| 19 | 458958881572 |
| 20 | 1872034052651 |
| 21 | 7633342954234 |
| 22 | 31116252892098 |
| 23 | 126806214027741 |
| 24 | 516633711969649 |