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 | 1 |
| 1 | 1 |
| 2 | 1 |
| 3 | 1 |
| 4 | 2 |
| 5 | 6 |
| 6 | 21 |
| 7 | 85 |
| 8 | 385 |
| 9 | 1907 |
| 10 | 10205 |
| 11 | 58455 |
| 12 | 355884 |
| 13 | 2290536 |
| 14 | 15518391 |
| 15 | 110283179 |
| 16 | 819675482 |
| 17 | 6355429550 |
| 18 | 51293023347 |
| 19 | 430062712439 |
| 20 | 3739408304962 |
| 21 | 33665192703946 |
| 22 | 313354708842791 |
| 23 | 3011545611755271 |
| 24 | 29847401178719637 |
| 25 | 304713973031878687 |
| 26 | 3201007359886598431 |