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 | 1 |
| 3 | 7 |
| 4 | 30 |
| 5 | 103 |
| 6 | 314 |
| 7 | 895 |
| 8 | 2455 |
| 9 | 6590 |
| 10 | 17480 |
| 11 | 46070 |
| 12 | 121016 |
| 13 | 317342 |
| 14 | 831465 |
| 15 | 2177613 |
| 16 | 5702054 |
| 17 | 14929365 |
| 18 | 39087010 |
| 19 | 102332805 |
| 20 | 267912735 |
| 21 | 701406940 |
| 22 | 1836309856 |
| 23 | 4807524652 |
| 24 | 12586266400 |
| 25 | 32951277148 |
| 26 | 86267567969 |
| 27 | 225851430035 |