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 | 0 |
| 1 | 1 |
| 2 | 2 |
| 3 | 14 |
| 4 | 82 |
| 5 | 593 |
| 6 | 4820 |
| 7 | 43980 |
| 8 | 444612 |
| 9 | 4934721 |
| 10 | 59661254 |
| 11 | 780531034 |
| 12 | 10987095718 |
| 13 | 165586966817 |
| 14 | 2660378564776 |
| 15 | 45392022568024 |
| 16 | 819716784789192 |
| 17 | 15620010933562689 |
| 18 | 313219935456042954 |
| 19 | 6593238655510464742 |
| 20 | 145364470356686267258 |
| 21 | 3349976056859294611697 |