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 | 5 |
| 3 | 18 |
| 4 | 104 |
| 5 | 943 |
| 6 | 12133 |
| 7 | 203038 |
| 8 | 4177755 |
| 9 | 101922814 |
| 10 | 2874725600 |
| 11 | 92009680557 |
| 12 | 3294276613933 |
| 13 | 130446181101044 |
| 14 | 5660055256165565 |
| 15 | 267044522107706072 |
| 16 | 13611243187516647324 |
| 17 | 745329728016955480687 |
| 18 | 43636132793651444511809 |
| 19 | 2719977663069107176768790 |