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 | 38980 |
| 9 | 347837 |
| 10 | 3448792 |
| 11 | 37614098 |
| 12 | 447530960 |
| 13 | 5768427763 |
| 14 | 80071232808 |
| 15 | 1190854748337 |
| 16 | 18891645882204 |
| 17 | 318426891675529 |
| 18 | 5682942507677216 |
| 19 | 107057693682517823 |
| 20 | 2122945762085834896 |
| 21 | 44202742291011618712 |
| 22 | 964190646266565855612 |