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 | 4 |
| 3 | 13 |
| 4 | 130 |
| 5 | 1210 |
| 6 | 33880 |
| 7 | 925771 |
| 8 | 75913222 |
| 9 | 6174066262 |
| 10 | 1506472167928 |
| 11 | 366573514642546 |
| 12 | 267598665689058580 |
| 13 | 195168545232713290660 |
| 14 | 427028776969176679964080 |
| 15 | 934054234760012359481199283 |
| 16 | 6129263888495201102915629695046 |