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) |
|---|---|
| 1 | 1 |
| 2 | 2 |
| 3 | 6 |
| 4 | 16 |
| 5 | 50 |
| 6 | 144 |
| 7 | 462 |
| 8 | 1392 |
| 9 | 4536 |
| 10 | 14060 |
| 11 | 46310 |
| 12 | 146376 |
| 13 | 485914 |
| 14 | 1557892 |
| 15 | 5202690 |
| 16 | 16861984 |
| 17 | 56579196 |
| 18 | 184940388 |
| 19 | 622945970 |
| 20 | 2050228360 |
| 21 | 6927964218 |
| 22 | 22930109884 |
| 23 | 77692142980 |
| 24 | 258360586368 |
| 25 | 877395996200 |
| 26 | 2929432171328 |
| 27 | 9968202968958 |
| 28 | 33396290888520 |
| 29 | 113837957337750 |