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 | 1 |
| 3 | 4 |
| 4 | 16 |
| 5 | 85 |
| 6 | 439 |
| 7 | 2358 |
| 8 | 12502 |
| 9 | 66471 |
| 10 | 351565 |
| 11 | 1855784 |
| 12 | 9765628 |
| 13 | 51271097 |
| 14 | 268554691 |
| 15 | 1403816410 |
| 16 | 7324218754 |
| 17 | 38147011723 |
| 18 | 198364257817 |
| 19 | 1029968457036 |
| 20 | 5340576171880 |
| 21 | 27656556152349 |
| 22 | 143051147460943 |
| 23 | 739097600097662 |
| 24 | 3814697265625006 |
| 25 | 19669532800292975 |