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 | 8 |
| 4 | 46 |
| 5 | 298 |
| 6 | 2206 |
| 7 | 19009 |
| 8 | 187076 |
| 9 | 2053349 |
| 10 | 24800484 |
| 11 | 327067043 |
| 12 | 4677505768 |
| 13 | 72075818159 |
| 14 | 1189985755128 |
| 15 | 20952274850927 |
| 16 | 391829421176768 |
| 17 | 7755079821666945 |
| 18 | 161926610838369418 |
| 19 | 3556807008080385549 |
| 20 | 81979632030102053376 |
| 21 | 1978135038931568355707 |