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 | 0 |
| 1 | 1 |
| 2 | 14 |
| 3 | 135 |
| 4 | 1228 |
| 5 | 11069 |
| 6 | 99642 |
| 7 | 896803 |
| 8 | 8071256 |
| 9 | 72641337 |
| 10 | 653772070 |
| 11 | 5883948671 |
| 12 | 52955538084 |
| 13 | 476599842805 |
| 14 | 4289398585298 |
| 15 | 38604587267739 |
| 16 | 347441285409712 |
| 17 | 3126971568687473 |
| 18 | 28142744118187326 |
| 19 | 253284697063686007 |
| 20 | 2279562273573174140 |
| 21 | 20516060462158567341 |