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 | 26 |
| 5 | 202 |
| 6 | 2462 |
| 7 | 43954 |
| 8 | 1063462 |
| 9 | 33076174 |
| 10 | 1270908802 |
| 11 | 58596709306 |
| 12 | 3170266564862 |
| 13 | 197764800466826 |
| 14 | 14024066291995502 |
| 15 | 1117378164606478094 |