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 | 0 |
| 1 | 1 |
| 2 | 23 |
| 3 | 507 |
| 4 | 11155 |
| 5 | 245411 |
| 6 | 5399043 |
| 7 | 118778947 |
| 8 | 2613136835 |
| 9 | 57489010371 |
| 10 | 1264758228163 |
| 11 | 27824681019587 |
| 12 | 612142982430915 |
| 13 | 13467145613480131 |
| 14 | 296277203496562883 |
| 15 | 6518098476924383427 |
| 16 | 143398166492336435395 |
| 17 | 3154759662831401578691 |
| 18 | 69404712582290834731203 |