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 | 3 |
| 2 | 14 |
| 3 | 45 |
| 4 | 124 |
| 5 | 315 |
| 6 | 762 |
| 7 | 1785 |
| 8 | 4088 |
| 9 | 9207 |
| 10 | 20470 |
| 11 | 45045 |
| 12 | 98292 |
| 13 | 212979 |
| 14 | 458738 |
| 15 | 983025 |
| 16 | 2097136 |
| 17 | 4456431 |
| 18 | 9437166 |
| 19 | 19922925 |
| 20 | 41943020 |
| 21 | 88080363 |
| 22 | 184549354 |
| 23 | 385875945 |
| 24 | 805306344 |
| 25 | 1677721575 |
| 26 | 3489660902 |
| 27 | 7247757285 |
| 28 | 15032385508 |