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 | 0 |
| 2 | 1 |
| 3 | 2 |
| 4 | 11 |
| 5 | 72 |
| 6 | 677 |
| 7 | 8686 |
| 8 | 152191 |
| 9 | 3632916 |
| 10 | 118317913 |
| 11 | 5271781946 |
| 12 | 322549557299 |
| 13 | 27208234437984 |
| 14 | 3177021912874253 |
| 15 | 515436469519284358 |
| 16 | 116581257420399219175 |
| 17 | 36866447823471507563436 |
| 18 | 16339685138335030408029889 |
| 19 | 10170100145132835334268145362 |