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 | 1 |
| 3 | 1 |
| 4 | 1 |
| 5 | 1 |
| 6 | 3 |
| 7 | 5 |
| 8 | 9 |
| 9 | 23 |
| 10 | 75 |
| 11 | 421 |
| 12 | 1103 |
| 13 | 5047 |
| 14 | 41783 |
| 15 | 281527 |
| 16 | 2534423 |
| 17 | 14161887 |
| 18 | 232663909 |
| 19 | 3988834875 |
| 20 | 45788778247 |
| 21 | 805144998681 |
| 22 | 14980361322965 |
| 23 | 620933643034787 |
| 24 | 16379818848380849 |
| 25 | 369622905371172929 |
| 26 | 20278641689337631649 |
| 27 | 995586066665500470689 |