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 | 4 |
| 2 | 13 |
| 3 | 45 |
| 4 | 161 |
| 5 | 588 |
| 6 | 2178 |
| 7 | 8151 |
| 8 | 30745 |
| 9 | 116688 |
| 10 | 445094 |
| 11 | 1704794 |
| 12 | 6552378 |
| 13 | 25258600 |
| 14 | 97617060 |
| 15 | 378098955 |
| 16 | 1467343305 |
| 17 | 5704370760 |
| 18 | 22210199550 |
| 19 | 86595896310 |
| 20 | 338052201630 |
| 21 | 1321178419080 |
| 22 | 5168764845660 |
| 23 | 20240517205350 |