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 | 1 |
| 2 | 2 |
| 3 | 6 |
| 4 | 36 |
| 5 | 325 |
| 6 | 3924 |
| 7 | 58996 |
| 8 | 1049088 |
| 9 | 21526641 |
| 10 | 500010000 |
| 11 | 12968792826 |
| 12 | 371504434176 |
| 13 | 11649044974645 |
| 14 | 396857394156608 |
| 15 | 14596463098125000 |
| 16 | 576460752571858944 |
| 17 | 24330595941321312961 |
| 18 | 1092955779880368226560 |
| 19 | 52063675149116964615310 |
| 20 | 2621440000000512000000000 |