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 | 9 |
| 2 | 19 |
| 3 | 47 |
| 4 | 113 |
| 5 | 273 |
| 6 | 659 |
| 7 | 1591 |
| 8 | 3841 |
| 9 | 9273 |
| 10 | 22387 |
| 11 | 54047 |
| 12 | 130481 |
| 13 | 315009 |
| 14 | 760499 |
| 15 | 1836007 |
| 16 | 4432513 |
| 17 | 10701033 |
| 18 | 25834579 |
| 19 | 62370191 |
| 20 | 150574961 |
| 21 | 363520113 |
| 22 | 877615187 |
| 23 | 2118750487 |
| 24 | 5115116161 |
| 25 | 12348982809 |
| 26 | 29813081779 |
| 27 | 71975146367 |