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 | 0 |
| 2 | 1 |
| 3 | 3 |
| 4 | 5 |
| 5 | 17 |
| 6 | 140 |
| 7 | 375 |
| 8 | 1090 |
| 9 | 11753 |
| 10 | 373581 |
| 11 | 1278347 |
| 12 | 13637279 |
| 13 | 163618153 |
| 14 | 27924949575 |
| 15 | 57188675627613 |
| 16 | 610029725544935 |
| 17 | 117122198574078151 |
| 18 | 19988890974450988558 |
| 19 | 239866235837773427391 |
| 20 | 12281151167363439030630 |
| 21 | 714539773759750811945040 |
| 22 | 6986623779812404246388298 |
| 23 | 1609715048049410062316011928 |
| 24 | 5993993484832111940013400809611 |