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) |
|---|---|
| 1 | 1 |
| 2 | 3 |
| 3 | 21 |
| 4 | 217 |
| 5 | 2910 |
| 6 | 47598 |
| 7 | 915221 |
| 8 | 20182962 |
| 9 | 501463686 |
| 10 | 13849394018 |
| 11 | 420676546425 |
| 12 | 13933516789491 |
| 13 | 499667134001968 |
| 14 | 19284476610918801 |
| 15 | 796927418729315367 |
| 16 | 35106627960374772536 |
| 17 | 1642235046999495643086 |
| 18 | 81296320098443729853915 |
| 19 | 4245930159553383360368993 |