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 | 2 |
| 2 | 3 |
| 3 | 9 |
| 4 | 39 |
| 5 | 252 |
| 6 | 2361 |
| 7 | 32077 |
| 8 | 631058 |
| 9 | 18035534 |
| 10 | 751936149 |
| 11 | 45973362492 |
| 12 | 4144777181393 |
| 13 | 554100538432001 |
| 14 | 110435083963283354 |
| 15 | 32981178674724868365 |