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 | 1 |
| 3 | 2 |
| 4 | 5 |
| 5 | 16 |
| 6 | 54 |
| 7 | 212 |
| 8 | 827 |
| 9 | 3369 |
| 10 | 13653 |
| 11 | 56052 |
| 12 | 229004 |
| 13 | 939935 |
| 14 | 3843859 |
| 15 | 15753903 |
| 16 | 64380796 |
| 17 | 263475472 |
| 18 | 1075780425 |
| 19 | 4397161320 |
| 20 | 17939394036 |
| 21 | 73251877235 |
| 22 | 298646347226 |
| 23 | 1218453344740 |