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 | 33 |
| 3 | 387 |
| 4 | 4161 |
| 5 | 42243 |
| 6 | 413793 |
| 7 | 3959427 |
| 8 | 37281921 |
| 9 | 347066883 |
| 10 | 3204309153 |
| 11 | 29403732867 |
| 12 | 268588249281 |
| 13 | 2444976817923 |
| 14 | 22198569382113 |
| 15 | 201143570584707 |
| 16 | 1819787258282241 |
| 17 | 16444551185679363 |
| 18 | 148466221699088673 |
| 19 | 1339452822487618947 |
| 20 | 12077873192759316801 |
| 21 | 108860443267429075203 |