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 | 12 |
| 5 | 60 |
| 6 | 180 |
| 7 | 1260 |
| 8 | 2520 |
| 9 | 7560 |
| 10 | 37800 |
| 11 | 415800 |
| 12 | 1247400 |
| 13 | 16216200 |
| 14 | 113513400 |
| 15 | 567567000 |
| 16 | 1135134000 |
| 17 | 19297278000 |
| 18 | 57891834000 |
| 19 | 1099944846000 |
| 20 | 5499724230000 |
| 21 | 38498069610000 |
| 22 | 423478765710000 |
| 23 | 9740011611330000 |