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 | 5 |
| 2 | 66 |
| 3 | 686 |
| 4 | 6721 |
| 5 | 58616 |
| 6 | 476781 |
| 7 | 3608348 |
| 8 | 25781989 |
| 9 | 174810494 |
| 10 | 1132328205 |
| 11 | 7037425172 |
| 12 | 42140788751 |
| 13 | 243918472743 |
| 14 | 1368647208107 |
| 15 | 7462686474948 |
| 16 | 39626100989332 |
| 17 | 205283558905562 |
| 18 | 1039263967957447 |
| 19 | 5149048724566723 |
| 20 | 24998922141116056 |
| 21 | 119073277412589351 |