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 | 2 |
| 2 | 15 |
| 3 | 155 |
| 4 | 1854 |
| 5 | 24124 |
| 6 | 331575 |
| 7 | 4736345 |
| 8 | 69616637 |
| 9 | 1046054129 |
| 10 | 15995716263 |
| 11 | 248111418112 |
| 12 | 3894303176880 |
| 13 | 61737213540306 |
| 14 | 987116931080661 |
| 15 | 15899835212249761 |
| 16 | 257758369219909534 |
| 17 | 4202381519278498915 |
| 18 | 68859442092723799788 |
| 19 | 1133401910867109123200 |