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) |
|---|---|
| 4 | 1 |
| 5 | 3 |
| 6 | 13 |
| 7 | 45 |
| 8 | 164 |
| 9 | 527 |
| 10 | 1652 |
| 11 | 4876 |
| 12 | 14000 |
| 13 | 38800 |
| 14 | 105112 |
| 15 | 278104 |
| 16 | 722736 |
| 17 | 1846320 |
| 18 | 4650368 |
| 19 | 11560320 |
| 20 | 28413312 |
| 21 | 69111168 |
| 22 | 166551680 |
| 23 | 397975680 |
| 24 | 943672576 |
| 25 | 2221821184 |
| 26 | 5197313024 |
| 27 | 12084884480 |
| 28 | 27944656896 |
| 29 | 64286203904 |
| 30 | 147182565376 |