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 | 3 |
| 2 | 13 |
| 3 | 76 |
| 4 | 542 |
| 5 | 4493 |
| 6 | 42131 |
| 7 | 439031 |
| 8 | 5020105 |
| 9 | 62382279 |
| 10 | 835980065 |
| 11 | 12004984120 |
| 12 | 183754242626 |
| 13 | 2984264710781 |
| 14 | 51220227153987 |
| 15 | 925859588215096 |
| 16 | 17571969962025822 |
| 17 | 349210371834021295 |
| 18 | 7249185099929421649 |
| 19 | 156847124089924073770 |
| 20 | 3530125495029323284404 |