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 | 0 |
| 2 | 3 |
| 3 | 29 |
| 4 | 397 |
| 5 | 6879 |
| 6 | 144751 |
| 7 | 3587100 |
| 8 | 102351929 |
| 9 | 3305310065 |
| 10 | 119186370091 |
| 11 | 4746969337923 |
| 12 | 206966647324933 |
| 13 | 9804683604806908 |
| 14 | 501491905963040903 |
| 15 | 27544070654283355889 |
| 16 | 1616869985889305862385 |
| 17 | 101020181695996141703335 |
| 18 | 6693303018177050431484035 |
| 19 | 468770856837303230888704208 |