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 | 6 |
| 2 | 21 |
| 3 | 56 |
| 4 | 231 |
| 5 | 462 |
| 6 | 4291 |
| 7 | 6966 |
| 8 | 57561 |
| 9 | 188866 |
| 10 | 1519035 |
| 11 | 3302922 |
| 12 | 45921281 |
| 13 | 83747286 |
| 14 | 933081411 |
| 15 | 3920355712 |
| 16 | 22075451286 |
| 17 | 62230996506 |
| 18 | 940379310731 |
| 19 | 1781757016326 |
| 20 | 22856965214727 |
| 21 | 87052415641136 |
| 22 | 598280600648031 |
| 23 | 1560731765058606 |
| 24 | 24680195365765751 |
| 25 | 56860576713326910 |
| 26 | 546736312124316741 |
| 27 | 2105947271634851386 |