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 | 5 |
| 3 | 35 |
| 4 | 369 |
| 5 | 4655 |
| 6 | 63600 |
| 7 | 901971 |
| 8 | 13079255 |
| 9 | 192622052 |
| 10 | 2870671950 |
| 11 | 43191857688 |
| 12 | 654999700403 |
| 13 | 9999088822075 |
| 14 | 153511100594603 |
| 15 | 2368347037571252 |
| 16 | 36695016991712879 |
| 17 | 570694242129491412 |
| 18 | 8905339105809603405 |
| 19 | 139377733711832678648 |
| 20 | 2187263896664830239467 |
| 21 | 34408176607279501779592 |