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) |
|---|---|
| 1 | 20 |
| 2 | 1218 |
| 3 | 7540 |
| 4 | 20280 |
| 5 | 1373090 |
| 6 | 4903600 |
| 7 | 23308460 |
| 8 | 316540365 |
| 9 | 527813814 |
| 10 | 4091661910 |
| 11 | 16718044954 |
| 12 | 1034412600 |
| 13 | 142903074740 |
| 14 | 1827252574658 |
| 15 | 31036383127940 |