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 | 0 |
| 2 | 1 |
| 3 | 9 |
| 4 | 20457529 |
| 5 | 143784081 |
| 6 | 331130809 |
| 7 | 20074072489 |
| 8 | 1193532215121 |
| 9 | 10036851273801 |
| 10 | 41413201925481 |
| 11 | 155991531977649 |
| 12 | 320642706437001 |
| 13 | 4665141483989281 |
| 14 | 87463589042698969 |
| 15 | 152191954834044129 |