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 | 2 |
| 3 | 5 |
| 4 | 18 |
| 5 | 81 |
| 6 | 448 |
| 7 | 2920 |
| 8 | 21955 |
| 9 | 186981 |
| 10 | 1779170 |
| 11 | 18706222 |
| 12 | 215364181 |
| 13 | 2694650157 |
| 14 | 36408144034 |
| 15 | 528302958022 |
| 16 | 8193953571315 |
| 17 | 135277259197031 |
| 18 | 2368556730208679 |
| 19 | 43838335667451773 |
| 20 | 855200666797199814 |
| 21 | 17538187897491897945 |
| 22 | 377199969925672569364 |
| 23 | 8489656058119117230574 |