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 | 70 |
| 2 | 1764 |
| 3 | 24696 |
| 4 | 232848 |
| 5 | 1646568 |
| 6 | 9343620 |
| 7 | 44537922 |
| 8 | 184225041 |
| 9 | 677352676 |
| 10 | 2254684432 |
| 11 | 6892441920 |
| 12 | 19571505408 |
| 13 | 52101067968 |
| 14 | 131018862096 |
| 15 | 313203587004 |
| 16 | 715536058545 |
| 17 | 1569305708586 |
| 18 | 3316911815140 |
| 19 | 6778924352200 |
| 20 | 13435361082000 |