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 | 12 |
| 3 | 33 |
| 4 | 96 |
| 5 | 317 |
| 6 | 1218 |
| 7 | 5425 |
| 8 | 27608 |
| 9 | 158129 |
| 10 | 1006574 |
| 11 | 7048657 |
| 12 | 53847420 |
| 13 | 445643681 |
| 14 | 3971876930 |
| 15 | 37928628529 |
| 16 | 386337833232 |
| 17 | 4181155148673 |
| 18 | 47912508680086 |
| 19 | 579538956964241 |
| 20 | 7378919177090244 |
| 21 | 98648882783190305 |