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 | 6 |
| 4 | 33 |
| 5 | 281 |
| 6 | 3111 |
| 7 | 41343 |
| 8 | 635202 |
| 9 | 11036914 |
| 10 | 213638812 |
| 11 | 4555901812 |
| 12 | 106107724162 |
| 13 | 2679887230354 |
| 14 | 72962091956750 |
| 15 | 2130453028323070 |
| 16 | 66421485491085025 |
| 17 | 2202438789394598209 |
| 18 | 77400308039913410963 |