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 | 22 |
| 3 | 146 |
| 4 | 1079 |
| 5 | 8525 |
| 6 | 70468 |
| 7 | 601816 |
| 8 | 5268241 |
| 9 | 47019566 |
| 10 | 426250277 |
| 11 | 3914020148 |
| 12 | 36328457669 |
| 13 | 340278596273 |
| 14 | 3212416054283 |
| 15 | 30534649412247 |
| 16 | 291981031204917 |
| 17 | 2806832429353512 |
| 18 | 27109863184695640 |
| 19 | 262951127248539898 |
| 20 | 2560229132085602215 |