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 | 1 |
| 2 | 1 |
| 3 | 13 |
| 4 | 49 |
| 5 | 201 |
| 6 | 2161 |
| 7 | 12629 |
| 8 | 102817 |
| 9 | 1118161 |
| 10 | 9109921 |
| 11 | 105660765 |
| 12 | 1223720785 |
| 13 | 13461561881 |
| 14 | 186666204817 |
| 15 | 2406325357861 |
| 16 | 33607592404033 |
| 17 | 516511765519521 |
| 18 | 7658010172957249 |
| 19 | 126206019752173997 |
| 20 | 2115466479287184241 |
| 21 | 36218229615683409001 |
| 22 | 666810643855970901937 |