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 | 4 |
| 4 | 10 |
| 5 | 32 |
| 6 | 133 |
| 7 | 706 |
| 8 | 4542 |
| 9 | 33770 |
| 10 | 284519 |
| 11 | 2694100 |
| 12 | 28292286 |
| 13 | 324935676 |
| 14 | 4052477864 |
| 15 | 54679031852 |
| 16 | 793359552994 |
| 17 | 12294933375782 |
| 18 | 202713354823112 |
| 19 | 3547535843321377 |
| 20 | 65667058958304601 |
| 21 | 1280634899889213903 |