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 | 2 |
| 2 | 5 |
| 3 | 16 |
| 4 | 47 |
| 5 | 146 |
| 6 | 447 |
| 7 | 1380 |
| 8 | 4251 |
| 9 | 13102 |
| 10 | 40343 |
| 11 | 124136 |
| 12 | 381625 |
| 13 | 1172198 |
| 14 | 3597401 |
| 15 | 11031012 |
| 16 | 33798339 |
| 17 | 103477590 |
| 18 | 316581567 |
| 19 | 967900224 |
| 20 | 2957316429 |
| 21 | 9030317478 |
| 22 | 27558851565 |
| 23 | 84059345244 |
| 24 | 256265811333 |
| 25 | 780885245826 |
| 26 | 2378410969977 |
| 27 | 7241027262280 |