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 | 520 |
| 3 | 19710 |
| 4 | 266304 |
| 5 | 1953250 |
| 6 | 10249200 |
| 7 | 40353950 |
| 8 | 136348160 |
| 9 | 387952659 |
| 10 | 1015690000 |
| 11 | 2357949022 |
| 12 | 5248851840 |
| 13 | 10604501570 |
| 14 | 20984054000 |
| 15 | 38498557500 |
| 16 | 69810262016 |
| 17 | 118587881410 |
| 18 | 201735382680 |
| 19 | 322687704638 |
| 20 | 520158288000 |
| 21 | 795376354500 |
| 22 | 1226133491440 |
| 23 | 1801152673630 |