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 | 18 |
| 4 | 16 |
| 5 | 1550 |
| 6 | 2598 |
| 7 | 299586 |
| 8 | 812 |
| 9 | 29118 |
| 10 | 348678430 |
| 11 | 67546215506 |
| 12 | 20345040 |
| 13 | 61054982557998 |
| 14 | 281241170407078 |
| 15 | 76861433640456450 |
| 16 | 2690404 |
| 17 | 128583032925805678334 |
| 18 | 211927625850 |
| 19 | 275941052631578947368402 |
| 20 | 174339200 |