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 | 44 |
| 3 | 580 |
| 4 | 8092 |
| 5 | 116304 |
| 6 | 1703636 |
| 7 | 25288120 |
| 8 | 379061020 |
| 9 | 5724954544 |
| 10 | 86981744944 |
| 11 | 1327977811076 |
| 12 | 20356299454276 |
| 13 | 313095240079600 |
| 14 | 4829571309488760 |
| 15 | 74683398325804080 |
| 16 | 1157402982351003420 |
| 17 | 17971185794898859248 |