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) |
|---|---|
| 1 | 2 |
| 2 | 6 |
| 3 | 18 |
| 4 | 50 |
| 5 | 142 |
| 6 | 390 |
| 7 | 1086 |
| 8 | 2958 |
| 9 | 8134 |
| 10 | 22050 |
| 11 | 60146 |
| 12 | 162466 |
| 13 | 440750 |
| 14 | 1187222 |
| 15 | 3208298 |
| 16 | 8622666 |
| 17 | 23233338 |
| 18 | 62329366 |
| 19 | 167558310 |
| 20 | 448848582 |
| 21 | 1204403014 |
| 22 | 3222280242 |
| 23 | 8633306906 |
| 24 | 23073198658 |
| 25 | 61740677454 |
| 26 | 164856393110 |
| 27 | 440658745814 |