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 | 9 |
| 2 | 71 |
| 3 | 580 |
| 4 | 5104 |
| 5 | 48860 |
| 6 | 509004 |
| 7 | 5753736 |
| 8 | 70290936 |
| 9 | 924118272 |
| 10 | 13020978816 |
| 11 | 195869441664 |
| 12 | 3134328981120 |
| 13 | 53180752331520 |
| 14 | 953884282141440 |
| 15 | 18037635241029120 |
| 16 | 358689683932346880 |
| 17 | 7483713725055744000 |
| 18 | 163478034254755584000 |
| 19 | 3731670622213083648000 |