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 | 5 |
| 2 | 15 |
| 3 | 44 |
| 4 | 160 |
| 5 | 604 |
| 6 | 2510 |
| 7 | 10545 |
| 8 | 45825 |
| 9 | 201669 |
| 10 | 900307 |
| 11 | 4057625 |
| 12 | 18447565 |
| 13 | 84444000 |
| 14 | 388878560 |
| 15 | 1799985435 |
| 16 | 8368841895 |
| 17 | 39062428790 |
| 18 | 182961584260 |
| 19 | 859612223990 |
| 20 | 4049955449888 |
| 21 | 19128675877279 |
| 22 | 90553562670495 |
| 23 | 429560546547595 |
| 24 | 2041573370075675 |
| 25 | 9719864998575489 |
| 26 | 46350124359578975 |
| 27 | 221352533355568044 |