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 | 1 |
| 2 | 2 |
| 3 | 4 |
| 4 | 10 |
| 5 | 23 |
| 6 | 63 |
| 7 | 155 |
| 8 | 448 |
| 9 | 1152 |
| 10 | 3452 |
| 11 | 9158 |
| 12 | 28178 |
| 13 | 76539 |
| 14 | 240369 |
| 15 | 665127 |
| 16 | 2123408 |
| 17 | 5964627 |
| 18 | 19301713 |
| 19 | 54897139 |
| 20 | 179687084 |
| 21 | 516448412 |
| 22 | 1707004865 |
| 23 | 4950415081 |
| 24 | 16501638058 |
| 25 | 48228801029 |
| 26 | 161963084065 |
| 27 | 476588705579 |
| 28 | 1611037922998 |
| 29 | 4769064680579 |
| 30 | 16215807145689 |