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 | 1 |
| 2 | 1 |
| 3 | 2 |
| 4 | 5 |
| 5 | 14 |
| 6 | 42 |
| 7 | 133 |
| 8 | 442 |
| 9 | 1537 |
| 10 | 5583 |
| 11 | 21165 |
| 12 | 83707 |
| 13 | 345324 |
| 14 | 1485687 |
| 15 | 6663354 |
| 16 | 31134078 |
| 17 | 151408319 |
| 18 | 765462514 |
| 19 | 4017644518 |
| 20 | 21860398111 |
| 21 | 123120413119 |
| 22 | 716701884408 |
| 23 | 4305828784896 |
| 24 | 26661920519485 |
| 25 | 169937265101628 |
| 26 | 1113616036893636 |
| 27 | 7494786443901137 |