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) |
|---|---|
| 2 | 3 |
| 3 | 16 |
| 4 | 55 |
| 5 | 156 |
| 6 | 399 |
| 7 | 960 |
| 8 | 2223 |
| 9 | 5020 |
| 10 | 11143 |
| 11 | 24432 |
| 12 | 53079 |
| 13 | 114492 |
| 14 | 245535 |
| 15 | 524032 |
| 16 | 1113823 |
| 17 | 2358972 |
| 18 | 4980375 |
| 19 | 10485360 |
| 20 | 22019655 |
| 21 | 46136860 |
| 22 | 96468463 |
| 23 | 201326016 |
| 24 | 419429775 |
| 25 | 872414556 |
| 26 | 1811938599 |
| 27 | 3758095600 |
| 28 | 7784627383 |
| 29 | 16106126460 |
| 30 | 33285995583 |
| 31 | 68719475712 |