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 | 4 |
| 2 | 34 |
| 3 | 334 |
| 4 | 3478 |
| 5 | 37384 |
| 6 | 409960 |
| 7 | 4558306 |
| 8 | 51199558 |
| 9 | 579554056 |
| 10 | 6600532684 |
| 11 | 75546800476 |
| 12 | 868224027916 |
| 13 | 10012494936136 |
| 14 | 115804853315332 |
| 15 | 1342795688895754 |
| 16 | 15604522381828678 |
| 17 | 181690692393744376 |
| 18 | 2119144763079629452 |
| 19 | 24754486729805925124 |
| 20 | 289563977079418497748 |