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 | 5 |
| 3 | 77 |
| 4 | 252 |
| 5 | 525 |
| 6 | 1221 |
| 7 | 2112 |
| 8 | 21312 |
| 9 | 56165 |
| 10 | 73437 |
| 11 | 276672 |
| 12 | 1265621 |
| 13 | 2114112 |
| 14 | 2509052 |
| 15 | 29311392 |
| 16 | 69555596 |
| 17 | 71588517 |
| 18 | 122434221 |
| 19 | 126000621 |
| 20 | 540888045 |
| 21 | 5401221045 |
| 22 | 21183638112 |
| 23 | 69069096096 |
| 24 | 71149694117 |
| 25 | 79158385197 |
| 26 | 2752360632572 |
| 27 | 7320655560237 |
| 28 | 12278611687221 |