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 | 4 |
| 2 | 30 |
| 3 | 303 |
| 4 | 3053 |
| 5 | 30421 |
| 6 | 303857 |
| 7 | 3039127 |
| 8 | 30395383 |
| 9 | 303963673 |
| 10 | 3039652332 |
| 11 | 30396399068 |
| 12 | 303963519954 |
| 13 | 3039635209356 |
| 14 | 30396355530761 |
| 15 | 303963552535238 |
| 16 | 3039635510867921 |
| 17 | 30396355103617024 |
| 18 | 303963550950390745 |
| 19 | 3039635508820145344 |
| 20 | 30396355092470750098 |
| 21 | 303963550928711270447 |