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 | 1 |
| 2 | 2 |
| 3 | 6 |
| 4 | 24 |
| 5 | 119 |
| 6 | 708 |
| 7 | 4914 |
| 8 | 38982 |
| 9 | 347869 |
| 10 | 3449252 |
| 11 | 37620655 |
| 12 | 447627708 |
| 13 | 5769915215 |
| 14 | 80095218258 |
| 15 | 1191261103432 |
| 16 | 18898879914026 |
| 17 | 318562100279543 |
| 18 | 5685592510437500 |
| 19 | 107112079379106657 |
| 20 | 2124112747338010252 |
| 21 | 44228883790175992996 |
| 22 | 964801076036155315318 |