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 | 4 |
| 3 | 16 |
| 4 | 65 |
| 5 | 266 |
| 6 | 1092 |
| 7 | 4488 |
| 8 | 18447 |
| 9 | 75790 |
| 10 | 311168 |
| 11 | 1276496 |
| 12 | 5231954 |
| 13 | 21425236 |
| 14 | 87662200 |
| 15 | 358374960 |
| 16 | 1463921595 |
| 17 | 5975446230 |
| 18 | 24373220520 |
| 19 | 99348849600 |
| 20 | 404703270510 |
| 21 | 1647594225420 |
| 22 | 6703757163480 |