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 | 1 |
| 2 | 3 |
| 3 | 18 |
| 4 | 115 |
| 5 | 902 |
| 6 | 7722 |
| 7 | 70784 |
| 8 | 678251 |
| 9 | 6670586 |
| 10 | 66851992 |
| 11 | 677328214 |
| 12 | 6903177354 |
| 13 | 70490174298 |
| 14 | 718856047396 |
| 15 | 7304677030708 |
| 16 | 73837797474235 |
| 17 | 741722190452840 |
| 18 | 7402780597473820 |
| 19 | 73459355234486763 |
| 20 | 726095774886910232 |
| 21 | 7170907377415662763 |
| 22 | 71063833561266044578 |