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 | 5 |
| 3 | 50 |
| 4 | 437 |
| 5 | 3270 |
| 6 | 21720 |
| 7 | 160593 |
| 8 | 1209537 |
| 9 | 8999307 |
| 10 | 66054288 |
| 11 | 485082083 |
| 12 | 3583263174 |
| 13 | 26469863097 |
| 14 | 195317239597 |
| 15 | 1440271919247 |
| 16 | 10624063817149 |
| 17 | 78389991175482 |
| 18 | 578363501074881 |
| 19 | 4266856868607953 |
| 20 | 31478045125433448 |
| 21 | 232231064765922254 |
| 22 | 1713315860292710073 |