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 | 7 |
| 2 | 21 |
| 3 | 273 |
| 4 | 16401 |
| 5 | 1048593 |
| 6 | 4295032833 |
| 7 | 1099512676353 |
| 8 | 9007199256838145 |
| 9 | 302231455185132270387201 |
| 10 | 1208944266358702884257793 |
| 11 | 1329227995784915872903807060297121793 |
| 12 | 1393796574908163946347162983661240005427201 |