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 | 7 |
| 2 | 63 |
| 3 | 644 |
| 4 | 7105 |
| 5 | 82467 |
| 6 | 992446 |
| 7 | 12271512 |
| 8 | 154962990 |
| 9 | 1990038435 |
| 10 | 25909892008 |
| 11 | 341225775072 |
| 12 | 4537563627415 |
| 13 | 60842326873230 |
| 14 | 821692714673340 |
| 15 | 11167153485624304 |
| 16 | 152610018401940330 |
| 17 | 2095863415900961490 |
| 18 | 28910564819681953485 |
| 19 | 400379714692751795820 |