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 | 0 |
| 1 | 1 |
| 2 | 7 |
| 3 | 31 |
| 4 | 115 |
| 5 | 390 |
| 6 | 1254 |
| 7 | 3893 |
| 8 | 11789 |
| 9 | 35045 |
| 10 | 102695 |
| 11 | 297516 |
| 12 | 853932 |
| 13 | 2432041 |
| 14 | 6881395 |
| 15 | 19361995 |
| 16 | 54214939 |
| 17 | 151164018 |
| 18 | 419910354 |
| 19 | 1162585565 |
| 20 | 3209268665 |
| 21 | 8835468881 |
| 22 | 24266461007 |
| 23 | 66501634776 |
| 24 | 181882282200 |
| 25 | 496539007825 |
| 26 | 1353272290399 |
| 27 | 3682496714743 |