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 | 0 |
| 2 | 1 |
| 3 | 1 |
| 4 | 3 |
| 5 | 8 |
| 6 | 25 |
| 7 | 84 |
| 8 | 301 |
| 9 | 1139 |
| 10 | 4528 |
| 11 | 18849 |
| 12 | 81968 |
| 13 | 371622 |
| 14 | 1753164 |
| 15 | 8589608 |
| 16 | 43624741 |
| 17 | 229255133 |
| 18 | 1244544545 |
| 19 | 6968765313 |
| 20 | 40195073827 |
| 21 | 238527741350 |
| 22 | 1454722738679 |
| 23 | 9108812009826 |
| 24 | 58503226812174 |
| 25 | 385086101416594 |