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 | 1 |
| 3 | 4 |
| 4 | 13 |
| 5 | 46 |
| 6 | 241 |
| 7 | 1156 |
| 8 | 6889 |
| 9 | 44668 |
| 10 | 300241 |
| 11 | 2328976 |
| 12 | 18390901 |
| 13 | 159273544 |
| 14 | 1461200833 |
| 15 | 13995753136 |
| 16 | 144068872081 |
| 17 | 1531949061136 |
| 18 | 17259159775969 |
| 19 | 202543867724608 |
| 20 | 2474236899786781 |
| 21 | 31633380519660256 |
| 22 | 417760492214548561 |
| 23 | 5751414293905728064 |