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 | 11 |
| 3 | 131 |
| 4 | 1365 |
| 5 | 12883 |
| 6 | 113935 |
| 7 | 967455 |
| 8 | 8013983 |
| 9 | 65410751 |
| 10 | 529283583 |
| 11 | 4261449727 |
| 12 | 34213027327 |
| 13 | 274240586751 |
| 14 | 2196272295935 |
| 15 | 17580376055807 |
| 16 | 140687025184767 |
| 17 | 1125685164621823 |
| 18 | 9006288735567871 |
| 19 | 72053745778425855 |
| 20 | 576444534576513023 |
| 21 | 4611617848860868607 |