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 | 5 |
| 1 | 19 |
| 2 | 66 |
| 3 | 227 |
| 4 | 785 |
| 5 | 2739 |
| 6 | 9646 |
| 7 | 34268 |
| 8 | 122706 |
| 9 | 442510 |
| 10 | 1605956 |
| 11 | 5861481 |
| 12 | 21502585 |
| 13 | 79243395 |
| 14 | 293246550 |
| 15 | 1089264360 |
| 16 | 4059928950 |
| 17 | 15179606010 |
| 18 | 56917649820 |
| 19 | 213982542150 |
| 20 | 806429435994 |
| 21 | 3046017513198 |