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 | 1 |
| 1 | 2 |
| 2 | 15 |
| 3 | 40 |
| 4 | 221 |
| 5 | 702 |
| 6 | 3355 |
| 7 | 11780 |
| 8 | 52041 |
| 9 | 193402 |
| 10 | 817895 |
| 11 | 3138720 |
| 12 | 12953461 |
| 13 | 50618102 |
| 14 | 206059635 |
| 15 | 813476860 |
| 16 | 3286192481 |
| 17 | 13047914802 |
| 18 | 52482224575 |
| 19 | 209057202200 |
| 20 | 838843897101 |
| 21 | 3347530323502 |
| 22 | 13413657088715 |
| 23 | 53584020970740 |
| 24 | 214547906035321 |
| 25 | 857556157684202 |