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 | 1 |
| 2 | 6 |
| 3 | 21 |
| 4 | 108 |
| 5 | 370 |
| 6 | 1908 |
| 7 | 6587 |
| 8 | 34248 |
| 9 | 119142 |
| 10 | 623700 |
| 11 | 2182818 |
| 12 | 11487528 |
| 13 | 40391988 |
| 14 | 213451560 |
| 15 | 753295635 |
| 16 | 3993910416 |
| 17 | 14136717574 |
| 18 | 75152083716 |
| 19 | 266650874678 |
| 20 | 1420670333640 |
| 21 | 5050926317724 |
| 22 | 26960309526744 |
| 23 | 96015725922014 |