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 | 2 |
| 1 | 5 |
| 2 | 17 |
| 3 | 51 |
| 4 | 152 |
| 5 | 454 |
| 6 | 1364 |
| 7 | 4116 |
| 8 | 12469 |
| 9 | 37912 |
| 10 | 115674 |
| 11 | 354078 |
| 12 | 1087023 |
| 13 | 3346090 |
| 14 | 10324775 |
| 15 | 31927163 |
| 16 | 98918331 |
| 17 | 306999516 |
| 18 | 954242372 |
| 19 | 2970046250 |
| 20 | 9255121991 |
| 21 | 28870447577 |
| 22 | 90140917038 |
| 23 | 281668510339 |
| 24 | 880762642043 |
| 25 | 2755784313655 |
| 26 | 8627071301305 |
| 27 | 27019889359705 |