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 | 3 |
| 2 | 8 |
| 3 | 18 |
| 4 | 44 |
| 5 | 150 |
| 6 | 762 |
| 7 | 5096 |
| 8 | 40392 |
| 9 | 362970 |
| 10 | 3628910 |
| 11 | 39916932 |
| 12 | 479001756 |
| 13 | 6227020982 |
| 14 | 87178291410 |
| 15 | 1307674368240 |
| 16 | 20922789888272 |
| 17 | 355687428096306 |
| 18 | 6402373705728342 |
| 19 | 121645100408832380 |
| 20 | 2432902008176640420 |
| 21 | 51090942171709440462 |
| 22 | 1124000727777607680506 |