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 | 0 |
| 2 | 13 |
| 3 | 15 |
| 4 | 74 |
| 5 | 468 |
| 6 | 2036 |
| 7 | 10982 |
| 8 | 53440 |
| 9 | 271596 |
| 10 | 1360466 |
| 11 | 6832459 |
| 12 | 34345485 |
| 13 | 172485648 |
| 14 | 866676017 |
| 15 | 4353899691 |
| 16 | 21873626234 |
| 17 | 109891360736 |
| 18 | 552080909728 |
| 19 | 2773601514082 |
| 20 | 13934283247296 |
| 21 | 70004406947220 |
| 22 | 351694969884786 |