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 | 0 |
| 1 | 1 |
| 2 | 20 |
| 3 | 381 |
| 4 | 7240 |
| 5 | 137561 |
| 6 | 2613660 |
| 7 | 49659541 |
| 8 | 943531280 |
| 9 | 17927094321 |
| 10 | 340614792100 |
| 11 | 6471681049901 |
| 12 | 122961939948120 |
| 13 | 2336276859014281 |
| 14 | 44389260321271340 |
| 15 | 843395946104155461 |
| 16 | 16024522975978953760 |
| 17 | 304465936543600121441 |