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 | 5 |
| 2 | 36 |
| 3 | 286 |
| 4 | 2380 |
| 5 | 20349 |
| 6 | 177100 |
| 7 | 1560780 |
| 8 | 13884156 |
| 9 | 124403620 |
| 10 | 1121099408 |
| 11 | 10150595910 |
| 12 | 92263734836 |
| 13 | 841392966470 |
| 14 | 7694644696200 |
| 15 | 70539987842520 |
| 16 | 648045936942300 |
| 17 | 5964720367660956 |
| 18 | 54991682779774384 |
| 19 | 507749884105448600 |
| 20 | 4694436188839116720 |