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 | 4 |
| 4 | 15 |
| 5 | 69 |
| 6 | 468 |
| 7 | 4636 |
| 8 | 57453 |
| 9 | 896062 |
| 10 | 18463713 |
| 11 | 425177757 |
| 12 | 11997649372 |
| 13 | 385088898632 |
| 14 | 13280323588034 |
| 15 | 509456736126003 |