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 | 3 |
| 2 | 11 |
| 3 | 49 |
| 4 | 261 |
| 5 | 1631 |
| 6 | 11743 |
| 7 | 95901 |
| 8 | 876809 |
| 9 | 8877691 |
| 10 | 98641011 |
| 11 | 1193556233 |
| 12 | 15624736141 |
| 13 | 220048367319 |
| 14 | 3317652307271 |
| 15 | 53319412081141 |
| 16 | 909984632851473 |
| 17 | 16436597430879731 |
| 18 | 313262209859119579 |
| 19 | 6282647653285676001 |
| 20 | 132266266384961600021 |
| 21 | 2916471173788403280463 |