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) |
|---|---|
| 2 | 1 |
| 3 | 6 |
| 4 | 29 |
| 5 | 148 |
| 6 | 818 |
| 7 | 4964 |
| 8 | 32989 |
| 9 | 238931 |
| 10 | 1875750 |
| 11 | 15877954 |
| 12 | 144229155 |
| 13 | 1399818783 |
| 14 | 14459867443 |
| 15 | 158421403734 |
| 16 | 1835075534606 |
| 17 | 22410381524083 |
| 18 | 287792334374327 |
| 19 | 3877249814539076 |
| 20 | 54682843244983801 |
| 21 | 805762421350331195 |
| 22 | 12382437603795254667 |
| 23 | 198118073801089459039 |