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 | 4 |
| 2 | 28 |
| 3 | 172 |
| 4 | 1036 |
| 5 | 6220 |
| 6 | 37324 |
| 7 | 223948 |
| 8 | 1343692 |
| 9 | 8062156 |
| 10 | 48372940 |
| 11 | 290237644 |
| 12 | 1741425868 |
| 13 | 10448555212 |
| 14 | 62691331276 |
| 15 | 376147987660 |
| 16 | 2256887925964 |
| 17 | 13541327555788 |
| 18 | 81247965334732 |
| 19 | 487487792008396 |
| 20 | 2924926752050380 |
| 21 | 17549560512302284 |
| 22 | 105297363073813708 |
| 23 | 631784178442882252 |