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 | 6 |
| 3 | 33 |
| 4 | 380 |
| 5 | 3535 |
| 6 | 189714 |
| 7 | 285929 |
| 8 | 319735800 |
| 9 | 1160703963 |
| 10 | 145739620510 |
| 11 | 86294277091 |
| 12 | 10914811650686580 |
| 13 | 60229285882649 |
| 14 | 163637596919801624970 |
| 15 | 3392462704290802545 |
| 16 | 669084376596453009616 |
| 17 | 370468452361579892135179 |
| 18 | 157145213515550643044429571846 |