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 | 3 |
| 2 | 7 |
| 3 | 31 |
| 4 | 150 |
| 5 | 853 |
| 6 | 5251 |
| 7 | 35109 |
| 8 | 249332 |
| 9 | 1873214 |
| 10 | 14754858 |
| 11 | 121380083 |
| 12 | 1037889452 |
| 13 | 9197178411 |
| 14 | 84207477581 |
| 15 | 794810896751 |
| 16 | 7717524260040 |
| 17 | 76956293344620 |
| 18 | 786822019659120 |
| 19 | 8237319107295510 |
| 20 | 88193381907972840 |