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 | 1 |
| 2 | 3 |
| 3 | 15 |
| 4 | 82 |
| 5 | 495 |
| 6 | 3147 |
| 7 | 20812 |
| 8 | 141621 |
| 9 | 985287 |
| 10 | 6976369 |
| 11 | 50108232 |
| 12 | 364202415 |
| 13 | 2673756449 |
| 14 | 19797659586 |
| 15 | 147677816532 |
| 16 | 1108711280376 |
| 17 | 8371222635096 |
| 18 | 63525564996093 |
| 19 | 484243596619753 |
| 20 | 3706268752629237 |
| 21 | 28470703720193010 |
| 22 | 219432896755734137 |