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 | 3 |
| 2 | 9 |
| 3 | 30 |
| 4 | 107 |
| 5 | 396 |
| 6 | 1503 |
| 7 | 5820 |
| 8 | 22907 |
| 9 | 91371 |
| 10 | 368523 |
| 11 | 1500354 |
| 12 | 6157669 |
| 13 | 25448907 |
| 14 | 105821865 |
| 15 | 442409844 |
| 16 | 1858482563 |
| 17 | 7840766601 |
| 18 | 33207750819 |
| 19 | 141137445258 |
| 20 | 601768494201 |
| 21 | 2573246794374 |
| 22 | 11032997250357 |
| 23 | 47421297986868 |
| 24 | 204286464525165 |
| 25 | 881900059488741 |