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 | 10 |
| 2 | 155 |
| 3 | 2220 |
| 4 | 31265 |
| 5 | 429502 |
| 6 | 5796455 |
| 7 | 77009640 |
| 8 | 1009734835 |
| 9 | 13088591470 |
| 10 | 167965714273 |
| 11 | 2136403822060 |
| 12 | 26958029557805 |
| 13 | 337733366170870 |
| 14 | 4203655872002815 |
| 15 | 52010628718162744 |
| 16 | 639999271669543500 |
| 17 | 7835602953248681200 |
| 18 | 95484165081421513000 |