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 | 2 |
| 2 | 14 |
| 3 | 106 |
| 4 | 834 |
| 5 | 6732 |
| 6 | 55289 |
| 7 | 459742 |
| 8 | 3858524 |
| 9 | 32618022 |
| 10 | 277326906 |
| 11 | 2369003910 |
| 12 | 20315879480 |
| 13 | 174798617778 |
| 14 | 1508225204024 |
| 15 | 13045333585950 |
| 16 | 113076177711662 |
| 17 | 981982906771978 |
| 18 | 8542048596893910 |
| 19 | 74416362792323370 |
| 20 | 649168980344148876 |
| 21 | 5669882132589477798 |