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 | 2 |
| 3 | 7 |
| 4 | 42 |
| 5 | 372 |
| 6 | 4269 |
| 7 | 59047 |
| 8 | 946557 |
| 9 | 17175289 |
| 10 | 347208299 |
| 11 | 7730688884 |
| 12 | 187911183701 |
| 13 | 4951155672353 |
| 14 | 140575561645293 |
| 15 | 4279249948000903 |
| 16 | 139050095246322895 |
| 17 | 4804391579357016747 |
| 18 | 175902340755219278039 |
| 19 | 6803436418471129704925 |
| 20 | 277202774381386656583959 |
| 21 | 11868116969794805874111831 |