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 | 1 |
| 2 | 1 |
| 3 | 4 |
| 4 | 16 |
| 5 | 58 |
| 6 | 215 |
| 7 | 806 |
| 8 | 3051 |
| 9 | 11602 |
| 10 | 44307 |
| 11 | 169840 |
| 12 | 653204 |
| 13 | 2519314 |
| 14 | 9740350 |
| 15 | 37739300 |
| 16 | 146498531 |
| 17 | 569642584 |
| 18 | 2218322463 |
| 19 | 8650367796 |
| 20 | 33773500347 |
| 21 | 132008143328 |
| 22 | 516495270723 |
| 23 | 2022721237326 |
| 24 | 7928249018667 |
| 25 | 31100068617294 |