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 | 6 |
| 1 | 30 |
| 2 | 140 |
| 3 | 631 |
| 4 | 2786 |
| 5 | 12136 |
| 6 | 52368 |
| 7 | 224406 |
| 8 | 956516 |
| 9 | 4060038 |
| 10 | 17175132 |
| 11 | 72454075 |
| 12 | 304941386 |
| 13 | 1280898304 |
| 14 | 5371301504 |
| 15 | 22491017758 |
| 16 | 94055344244 |
| 17 | 392888085100 |
| 18 | 1639534704632 |
| 19 | 6835739258998 |
| 20 | 28477594607348 |
| 21 | 118551827347576 |