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 | 2 |
| 3 | 5 |
| 4 | 10 |
| 5 | 257 |
| 6 | 66 |
| 7 | 46657 |
| 8 | 16514 |
| 9 | 1679873 |
| 10 | 524290 |
| 11 | 10000000001 |
| 12 | 4200450 |
| 13 | 8916100448257 |
| 14 | 26121388034 |
| 15 | 4398314962945 |
| 16 | 35185445863426 |
| 17 | 18446744073709551617 |
| 18 | 33853319151618 |
| 19 | 39346408075296537575425 |
| 20 | 144115737832194050 |
| 21 | 3833763648605916233729 |
| 22 | 2000000000000000000002 |