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 | 3 |
| 1 | 3 |
| 2 | 5 |
| 3 | 11 |
| 4 | 31 |
| 5 | 131 |
| 6 | 733 |
| 7 | 5059 |
| 8 | 40351 |
| 9 | 362903 |
| 10 | 3628819 |
| 11 | 39916817 |
| 12 | 479001643 |
| 13 | 6227020873 |
| 14 | 87178291241 |
| 15 | 1307674368149 |
| 16 | 20922789888041 |
| 17 | 355687428096053 |
| 18 | 6402373705728061 |
| 19 | 121645100408832109 |
| 20 | 2432902008176640037 |
| 21 | 51090942171709440037 |