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 | 2 |
| 3 | 6 |
| 4 | 23 |
| 5 | 110 |
| 6 | 631 |
| 7 | 4223 |
| 8 | 32301 |
| 9 | 277962 |
| 10 | 2657797 |
| 11 | 27954521 |
| 12 | 320752991 |
| 13 | 3987045780 |
| 14 | 53372351265 |
| 15 | 765499019221 |
| 16 | 11711207065229 |
| 17 | 190365226548070 |
| 18 | 3276401870322033 |
| 19 | 59523410471007913 |
| 20 | 1138295039078030599 |
| 21 | 22856576346825690128 |
| 22 | 480807130959249565541 |