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 | 2 |
| 3 | 18 |
| 4 | 128 |
| 5 | 2500 |
| 6 | 15552 |
| 7 | 705894 |
| 8 | 8388608 |
| 9 | 258280326 |
| 10 | 4000000000 |
| 11 | 259374246010 |
| 12 | 2972033482752 |
| 13 | 279577021469772 |
| 14 | 4762288639524864 |
| 15 | 233543408203125000 |
| 16 | 9223372036854775808 |
| 17 | 778579070010669895696 |
| 18 | 13115469358432179191808 |
| 19 | 1874292305362402347591138 |