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 | 3 |
| 3 | 14 |
| 4 | 79 |
| 5 | 494 |
| 6 | 3294 |
| 7 | 22952 |
| 8 | 165127 |
| 9 | 1217270 |
| 10 | 9146746 |
| 11 | 69799476 |
| 12 | 539464358 |
| 13 | 4214095612 |
| 14 | 33218794236 |
| 15 | 263908187100 |
| 16 | 2110912146295 |
| 17 | 16985386737830 |
| 18 | 137394914285538 |
| 19 | 1116622717709012 |
| 20 | 9113225693455362 |
| 21 | 74659999210200292 |