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 | 26 |
| 6 | 74 |
| 7 | 222 |
| 8 | 698 |
| 9 | 2264 |
| 10 | 7536 |
| 11 | 25600 |
| 12 | 88406 |
| 13 | 309440 |
| 14 | 1095354 |
| 15 | 3914340 |
| 16 | 14102324 |
| 17 | 51165004 |
| 18 | 186774368 |
| 19 | 685495334 |
| 20 | 2527957006 |