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 | 4 |
| 2 | 22 |
| 3 | 156 |
| 4 | 1233 |
| 5 | 10420 |
| 6 | 92120 |
| 7 | 841376 |
| 8 | 7876616 |
| 9 | 75177492 |
| 10 | 728784802 |
| 11 | 7156081536 |
| 12 | 71024862452 |
| 13 | 711383912672 |
| 14 | 7181295333306 |
| 15 | 72989746391780 |
| 16 | 746308443708928 |
| 17 | 7671359593228624 |
| 18 | 79226966456758424 |
| 19 | 821691132077059740 |
| 20 | 8554576791134761387 |