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) |
|---|---|
| 1 | 1 |
| 2 | 3 |
| 3 | 11 |
| 4 | 68 |
| 5 | 630 |
| 6 | 7790 |
| 7 | 117664 |
| 8 | 2097224 |
| 9 | 43046801 |
| 10 | 1000000643 |
| 11 | 25937425245 |
| 12 | 743008378547 |
| 13 | 23298085130341 |
| 14 | 793714773371879 |
| 15 | 29192926025508929 |
| 16 | 1152921504608944840 |
| 17 | 48661191875668966346 |
| 18 | 2185911559738739586562 |
| 19 | 104127350297911284587436 |