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 | 1 |
| 2 | 7 |
| 3 | 58 |
| 4 | 505 |
| 5 | 4498 |
| 6 | 40576 |
| 7 | 368965 |
| 8 | 3373225 |
| 9 | 30958240 |
| 10 | 284934754 |
| 11 | 2628211291 |
| 12 | 24283705558 |
| 13 | 224677646416 |
| 14 | 2081054132179 |
| 15 | 19293026227024 |
| 16 | 178996540057615 |
| 17 | 1661743445778403 |
| 18 | 15435351753092176 |
| 19 | 143439377236572826 |
| 20 | 1333496145331028230 |