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 | 1 |
| 1 | 3 |
| 2 | 13 |
| 3 | 147 |
| 4 | 1681 |
| 5 | 18733 |
| 6 | 204205 |
| 7 | 2195399 |
| 8 | 23429185 |
| 9 | 249258777 |
| 10 | 2650436845 |
| 11 | 28209301211 |
| 12 | 300745906449 |
| 13 | 3212758605189 |
| 14 | 34392151363021 |
| 15 | 368908132170511 |
| 16 | 3964622452867329 |
| 17 | 42682164804034609 |
| 18 | 460242445806795853 |