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 | 2 |
| 2 | 7 |
| 3 | 38 |
| 4 | 272 |
| 5 | 2444 |
| 6 | 26306 |
| 7 | 330588 |
| 8 | 4746360 |
| 9 | 76675584 |
| 10 | 1376187072 |
| 11 | 27171073632 |
| 12 | 585216675600 |
| 13 | 13655030234208 |
| 14 | 343124183767920 |
| 15 | 9237920561327904 |
| 16 | 265292717180631552 |
| 17 | 8094790891854169344 |
| 18 | 261522698597072168832 |
| 19 | 8918551194519088836864 |