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) |
|---|---|
| 0 | 1 |
| 1 | 1 |
| 2 | 4 |
| 3 | 30 |
| 4 | 312 |
| 5 | 3965 |
| 6 | 57824 |
| 7 | 933998 |
| 8 | 16346728 |
| 9 | 305539046 |
| 10 | 6037780164 |
| 11 | 125227212342 |
| 12 | 2711254371568 |
| 13 | 61021656441091 |
| 14 | 1423063422363676 |
| 15 | 34297379607790288 |
| 16 | 852463916004336464 |
| 17 | 21812807282389353798 |