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) |
|---|---|
| 1 | 0 |
| 2 | 1 |
| 3 | 2 |
| 4 | 6 |
| 5 | 18 |
| 6 | 61 |
| 7 | 224 |
| 8 | 890 |
| 9 | 3784 |
| 10 | 17113 |
| 11 | 81950 |
| 12 | 414230 |
| 13 | 2204110 |
| 14 | 12314109 |
| 15 | 72049548 |
| 16 | 440379770 |
| 17 | 2805266692 |
| 18 | 18584809833 |
| 19 | 127812870474 |
| 20 | 910990458022 |
| 21 | 6719535098378 |
| 22 | 51223251471453 |
| 23 | 403044829472760 |
| 24 | 3269538955148698 |
| 25 | 27314067026782976 |
| 26 | 234749040898160153 |