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 | 1 |
| 2 | 2 |
| 3 | 6 |
| 4 | 24 |
| 5 | 119 |
| 6 | 708 |
| 7 | 4914 |
| 8 | 38977 |
| 9 | 347783 |
| 10 | 3447982 |
| 11 | 37602245 |
| 12 | 447353497 |
| 13 | 5765670515 |
| 14 | 80026435959 |
| 15 | 1190091483826 |
| 16 | 18877998176267 |
| 17 | 318170909582504 |
| 18 | 5677911026433716 |
| 19 | 106954187252974515 |
| 20 | 2120720309936327198 |
| 21 | 44152804913927293967 |
| 22 | 963022839743497051427 |