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 | 5 |
| 3 | 16 |
| 4 | 49 |
| 5 | 142 |
| 6 | 415 |
| 7 | 1198 |
| 8 | 3473 |
| 9 | 10048 |
| 10 | 29118 |
| 11 | 84376 |
| 12 | 244747 |
| 13 | 710198 |
| 14 | 2062273 |
| 15 | 5991417 |
| 16 | 17416400 |
| 17 | 50652247 |
| 18 | 147384675 |
| 19 | 429043389 |
| 20 | 1249508946 |
| 21 | 3640449678 |
| 22 | 10610613551 |
| 23 | 30937605075 |
| 24 | 90237313082 |
| 25 | 263288153073 |
| 26 | 768449666116 |
| 27 | 2243530461066 |
| 28 | 6552016136666 |