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 | 3 |
| 2 | 10 |
| 3 | 80 |
| 4 | 556 |
| 5 | 3348 |
| 6 | 20596 |
| 7 | 134412 |
| 8 | 888232 |
| 9 | 5836068 |
| 10 | 38457456 |
| 11 | 255381636 |
| 12 | 1704162724 |
| 13 | 11399565860 |
| 14 | 76433483528 |
| 15 | 513785171540 |
| 16 | 3461284463632 |
| 17 | 23360156262164 |
| 18 | 157908381404144 |
| 19 | 1068981156413892 |
| 20 | 7246198178206132 |