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 | 3 |
| 3 | 9 |
| 4 | 29 |
| 5 | 96 |
| 6 | 326 |
| 7 | 1127 |
| 8 | 3952 |
| 9 | 14019 |
| 10 | 50208 |
| 11 | 181275 |
| 12 | 659039 |
| 13 | 2410433 |
| 14 | 8862750 |
| 15 | 32739168 |
| 16 | 121443136 |
| 17 | 452167865 |
| 18 | 1689237104 |
| 19 | 6330103627 |
| 20 | 23787215202 |
| 21 | 89616350271 |
| 22 | 338417312294 |
| 23 | 1280739676563 |
| 24 | 4856711761475 |
| 25 | 18451630811041 |
| 26 | 70223495698892 |
| 27 | 267691953822783 |