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 | 15 |
| 3 | 330 |
| 4 | 8415 |
| 5 | 232254 |
| 6 | 6735366 |
| 7 | 202060980 |
| 8 | 6213375135 |
| 9 | 194685754230 |
| 10 | 6191006984514 |
| 11 | 199237861137996 |
| 12 | 6475230486984870 |
| 13 | 212188322111965740 |
| 14 | 7002214629694869420 |
| 15 | 232473525705869664744 |
| 16 | 7758803920433400060831 |
| 17 | 260148131449825766745510 |
| 18 | 8758320425477467480432170 |