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 | 1 |
| 2 | 2 |
| 3 | 6 |
| 4 | 30 |
| 5 | 330 |
| 6 | 2310 |
| 7 | 53130 |
| 8 | 690690 |
| 9 | 20030010 |
| 10 | 821230410 |
| 11 | 13960916970 |
| 12 | 739928599410 |
| 13 | 27377358178170 |
| 14 | 2272320728788110 |
| 15 | 97709791337888730 |
| 16 | 8696171429072096970 |
| 17 | 165227257152369842430 |
| 18 | 18670680058217792194590 |