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 | 4 |
| 4 | 10 |
| 5 | 20 |
| 6 | 58 |
| 7 | 116 |
| 8 | 320 |
| 9 | 772 |
| 10 | 2170 |
| 11 | 4340 |
| 12 | 14112 |
| 13 | 28224 |
| 14 | 78120 |
| 15 | 212004 |
| 16 | 612232 |
| 17 | 1224464 |
| 18 | 3873760 |
| 19 | 7747520 |
| 20 | 24224608 |
| 21 | 64595088 |
| 22 | 175452168 |
| 23 | 350904336 |